SUBORDINATED LOAN AGREEMENT

Section 1.1                                                                                                                                         Definitions ................................................................................................................................1

Section 1.2                                                                                                                                         Other Definitional Provisions ........................................................................................5

Section 1.3                                                                                                                                         Accounting Terms and Principles . ...................................................................................6

Section 2.1                                                                                                                                         Subordinated Loan Commitment ......................................................................................6

Section 2.2                                                                                                                                        Borrowing Procedure ..........................................................................................................6

Section 2.3                                                                                                                                        Optional Reduction and Termination of Subordinated Loan Commitment .....6

Section 2.4                                                                                                                                         Repayment of Subordinated Loans ..................................................................................6

Section 2.5                                                                                                                                         Prepayment . ...............................................................................................................................6

Section 2.6                                                                                                                                         Interest on Subordinated Loans . ......................................................................................7

Section 2.7                                                                                                                                         Computation of Interest ......................................................................................................7

Section 2.8                                                                                                                                         Payments Generally . .............................................................................................................7

Section 3.1                                                                                                                                         Conditions to Effectiveness ...............................................................................................8

Section 3.2                                                                                                                                         Conditions to Making of each Subordinated Loan ....................................................8

Section 4.1                                                                                                                                         Financial Condition ................................................................................................................9

Section 4.2                                                                                                                                         No Change ..................................................................................................................................9

Section 4.3                                                                                                                                         Corporate Existence; Compliance with Law ...............................................................9

Section 4.4                                                                                                                                         Limited Partnership Power; Authorization; enforeable ligations ...................9

Section  4.5                                                                                                                                         No Legal Bar ...........................................................................................................................10

Section 4.6                                                                                                                                         No Material Litigation .......................................................................................................10

Section 4.7                                                                                                                                         No Default ................................................................................................................................10

Section 4.8                                                                                                                                         Ownership of Property ........................................................................................................10

Section 4.9                                                                                                                                         Use of Proceeds .......................................................................................................................10

Section 4.10                                                                                                                                       Margin Regulations ..............................................................................................................10

Section 4.11                                                                                                                                       Investment Company Act .....................................................................................................10

Section 5.1                                                                                                                                         Notice of Default ...................................................................................................................10

Section 6.1                                                                                                                                         Events of Default ..................................................................................................................11

Section 7.1                                                                                                                                         Notices . .......................................................................................................................................12

Section 7.2                                                                                                                                         Waiver; Amendments ..............................................................................................................13

Section 7.3                                                                                                                                         Expenses; Indemnification . ....................................................................................................13

Section 7.4                                                                                                                                         Successors and Assigns .........................................................................................................14

Section 7.5                                                                                                                                         Governing Law ..........................................................................................................................14

Section 7.6                                                                                                                                         Submission to Jurisdiction; Service of Process. .........................................................14

Section 7.7                                                                                                                                         Waiver of Jury Trial ..............................................................................................................15

Section 7.8                                                                                                                                         Counterparts; Integration ..................................................................................................15

Section 7.9                                                                                                                                         Survival .......................................................................................................................................15

Section 7.10                                                                                                                                      Severability ..............................................................................................................................15

Section 7.11                                                                                                                                       Non-recourse To The General Partner and Associated Persons .........................15

THIS SUBORDINATED LOAN AGREEMENT (this “ Agreement ”) is made and entered into as of May 1, 2009, by and between Boardwalk Pipelines Holding Corp., a Delaware corporation (the “ Lender ”), and Boardwalk Pipelines, LP, a Delaware limited partnership (the “ Borrower ”).

WHEREAS , the Borrower has requested that the Lender make subordinated loans to the Borrower in an aggregate principal amount of up to $200,000,000; and

WHEREAS , subject to the terms and conditions of this Agreement, the Lender is willing to make the requested subordinated loans to the Borrower.

NOW, THEREFORE , in consideration of the premises and the mutual covenants herein contained, the Borrower and the Lender agree as follows:

Section 1.1   Definitions

.  The following terms used herein shall have the meanings herein specified (to be equally applicable to both the singular and plural forms of the terms defined):

 “ Agreement ” shall have the meaning assigned to such term in the opening paragraph of this Agreement.

“ Associated Persons ” shall have the meaning set forth in Section 7.11 .

“ Availability Period ” shall mean the period from the Closing Date through the day prior to the first anniversary of the Closing Date.

“ Borrower ” shall have the meaning assigned to such term in the opening paragraph of this Agreement.

“ Borrower Affiliate ” shall mean each of the MLP, the General Partner, Boardwalk GP, LLC, each Subsidiary of the MLP and each Subsidiary of Boardwalk Pipelines, LP.

“ Business Day ” shall mean a day other than a Saturday, Sunday or other day on which commercial banks in New York City are authorized or required by law to close.

“ Capital Lease Obligations ” shall mean, with respect to any Person, the obligations of such Person to pay rent or other amounts under any lease of (or other arrangement conveying the right to use) real or personal property, or a combination thereof, which obligations are required to be classified and accounted for as capital leases on a balance sheet of such Person under GAAP; and, for the purposes of this Agreement, the amount of such obligations at any time shall be the capitalized amount thereof at such time determined in accordance with GAAP.

“ Capital Stock ” shall mean any and all shares, interests, participations or other equivalents (however designated) of capital stock of a corporation, any and all equivalent ownership interests in a Person (other than a corporation) and any and all warrants, rights or options to purchase any of the foregoing.

“ Closing Date ” shall have the meaning assigned to such term in Section 3.1.

“ Code ” shall mean the United States Internal Revenue Code of 1986, as amended from time to time.

“ Contractual Obligation ” shall mean as to any Person, any provision of any security issued by such Person or of any agreement, instrument or other undertaking to which such Person is a party or by which it or any of its Property is bound.

“ Default ” means any of the events specified in Article VI , whether or not any requirement for the giving of notice, the lapse of time, or both, has been satisfied.

“ Default Interest ” shall have the meaning set forth in Section 2.4(b) .

“ Default Interest Rate ” shall mean the Subordinated Loan Interest Rate, plus an additional 2% per annum.

“ Dollars ” and “ $ ” shall mean the lawful currency of the United States of America.

“ Event of Default ” shall mean any of the events specified in Article VI , provided that any requirement for the giving of notice, the lapse of time, or both, has been satisfied.

“ Fiscal 2008 10K ” shall have the meaning set forth in Section 4.1 .

“ GAAP ” shall mean generally accepted accounting principles in the United States applied on a consistent basis.

“ General Partner ” shall mean Boardwalk GP, LP, a Delaware limited partnership.

“ Governmental Authority ” shall mean any nation or government, any state or other political subdivision thereof and any entity exercising executive, legislative, judicial, regulatory or administrative functions of or pertaining to government.

“ Guarantee Obligation ” shall mean as to any Person (the “ guaranteeing person ”), any obligation of (a) the guaranteeing person or (b) another Person (including, without limitation, any bank under any letter of credit), if to induce the creation of such obligation of such other Person the guaranteeing person has issued a reimbursement, counterindemnity or similar obligation, in either case guaranteeing or in effect guaranteeing any Indebtedness, leases, dividends or other obligations (the “ primary obligations ”) of any other third Person (the “ primary obligor ”) in any manner, whether directly or indirectly, including, without limitation, any obligation of the guaranteeing person, whether or not contingent, (i) to purchase any such primary obligation or any Property constituting direct or indirect security therefor, (ii) to advance or supply funds (1) for the purchase or payment of any such primary obligation or (2) to maintain working capital or equity capital of the primary obligor or otherwise to maintain the net worth or solvency of the primary obligor, (iii) to purchase Property, securities or services primarily for the purpose of assuring the owner of any such primary obligation of the ability of the primary obligor to make payment of such primary obligation or (iv) otherwise to assure or hold harmless the owner of any such primary obligation against loss in respect thereof; provided, however , that the term Guarantee Obligation shall not include endorsements of instruments for deposit or collection in the ordinary course of business.  The amount of any Guarantee Obligation of any guaranteeing person shall be deemed to be the lower of (a) an amount equal to the stated or determinable amount of the primary obligation in respect of which such Guarantee Obligation is made and (b) the maximum amount for which such guaranteeing person may be liable pursuant to the terms of the instrument embodying such Guarantee Obligation, unless such primary obligation and the maximum amount for which such guaranteeing person may be liable are not stated or determinable, in which case the amount of such Guarantee Obligation shall be such guaranteeing person’s maximum reasonably anticipated liability in respect thereof as determined by the Borrower in good faith.

“ Hedge Agreements ” shall mean all interest rate or currency swaps, caps or collar agreements, foreign exchange agreements, commodity contracts or similar arrangements entered into by the Borrower or its Subsidiaries providing for protection against fluctuations in interest rates, currency exchange rates, commodity prices or the exchange of nominal interest obligations, either generally or under specific contingencies.

 “ Indebtedness ” shall mean of any Person at any date, without duplication, (a) all indebtedness of such Person for borrowed money, (b) all obligations of such Person for the deferred purchase price of Property or services (other than trade payables incurred in the ordinary course of such Person’s business), (c) all obligations of such Person evidenced by notes, bonds, debentures or other similar instruments, (d) all indebtedness created or arising under any conditional sale or other title retention agreement with respect to Property acquired by such Person (even though the rights and remedies of the seller or lender under such agreement in the event of default are limited to repossession or sale of such Property), (e) all Capital Lease Obligations of such Person, (f) all obligations of such Person, contingent or otherwise, as an account party or applicant under acceptance, letter of credit or similar facilities, (g) all obligations of such Person, contingent or otherwise, to purchase, redeem, retire or otherwise acquire for value any Capital Stock of such Person, (h) all Guarantee Obligations of such Person in respect of obligations of the kind referred to in clauses (a) through (g) above; (i) all obligations of the kind referred to in clauses (a) through (h) above secured by (or for which the holder of such obligation has an existing right, contingent or otherwise, to be secured by) any Lien on Property (including, without limitation, accounts and contract rights) owned by such Person, whether or not such Person has assumed or become liable for the payment of such obligation and (j) all obligations of such Person in respect of Hedge Agreements.

“ Lender ” shall have the meaning assigned to such term in the opening paragraph of this Agreement.

“ Lender Indemnitee ” shall mean Lender and any other Person that, directly or indirectly, is in control of the Lender, and each of the directors, officers, employees, agents, trustees, representatives, attorneys, consultants and advisors of or to any of the foregoing.  For purposes of this definition, “control” of a Person means the power, directly or indirectly, either to (a) vote 25% or more of the securities having ordinary voting power for the election of directors (or persons performing similar functions) of such Person or (b) direct or cause the direction of the management and policies of such Person, whether by contract or otherwise.

“ Lien ” shall mean any mortgage, pledge, hypothecation, assignment, deposit arrangement, encumbrance, lien (statutory or other), charge or other security interest or any preference, priority or other security agreement or preferential arrangement of any kind or nature whatsoever (including, without limitation, any conditional sale or other title retention agreement and any capital lease having substantially the same economic effect as any of the foregoing).

 “ Material Adverse Effect ” shall mean a material adverse effect on (a) the business, assets, liabilities, operations or condition (financial or otherwise) of the Borrower and its Subsidiaries taken as a whole, (b) the ability of the Borrower to perform its obligations under this Agreement or any other Subordinated Loan Document, or (c) the ability of the Lender to enforce this Agreement or any other Subordinated Loan Document.

“ Maturity Date ” shall mean the date that is six months after the later of (i) the Scheduled Maturity Date (as defined in the Senior Credit Agreement) and (ii) if a Term Out Period has become effective under the Senior Credit Agreement, the last day of the Term Out Period (as defined in the Senior Credit Agreement).

 “ MLP ” shall mean Boardwalk Pipeline Partners, LP, a Delaware limited partnership.

“ Net Cash Proceeds ” means the remainder of (a) the gross proceeds received by the MLP, the Borrower, or any Subsidiary of the Borrower, as the case may be, from the incurrence of Qualifying Indebtedness or the issuance of Qualifying Equity Securities, as applicable, less (b) underwriter discounts and commissions, investment banking fees, legal, accounting and other professional fees and expenses, taxes, and other usual and customary transaction costs.

“ Notice of Borrowing ” shall have the meaning set forth in Section 2.2 .

“ Obligations ” shall mean the unpaid principal of and interest on (including, without limitation, interest accruing after the maturity of the Subordinated Loans and interest accruing after the filing of any petition in bankruptcy, or the commencement of any insolvency, reorganization or like proceeding, relating to the Borrower, whether or not a claim for post-filing or post-petition interest is allowed in such proceeding) the Subordinated Loans and all other obligations and liabilities of the Borrower to the Lender, whether direct or indirect, absolute or contingent, due or to become due, or now existing or hereafter incurred, which may arise under, out of, or in connection with, this Agreement, any other Subordinated Loan Document, or any other document made, delivered or given in connection herewith or therewith, whether on account of principal, interest, reimbursement obligations, fees, indemnities, costs, expenses (including, without limitation, all fees, charges and disbursements of counsel to the Lender that are required to be paid by the Borrower pursuant hereto) or otherwise.

 “ Payment Office ” shall mean the office of the Lender located at 9 Greenway Plaza, Suite 2800, Houston, TX  77046, or such other location as to which the Lender shall have given written notice to the Borrower.

“ Person ” shall mean an individual, partnership, corporation, limited liability company, business trust, joint stock company, trust, unincorporated association, joint venture, Governmental Authority or other entity of whatever nature.

“ Property ” shall mean any right or interest in or to property of any kind whatsoever, whether real, personal  or mixed and whether tangible or intangible, including, without limitation, Capital Stock.

“ Qualifying Equity Securities ” means partnership interests in (or other ownership or profit interests in) the MLP, warrants, options or other rights for the purchase or acquisition from the MLP of partnership interests of (or other ownership or profit interests in) the MLP, and all of the other ownership or profit interests in the MLP, whether voting or nonvoting.

“ Qualifying Indebtedness ” means Indebtedness of the MLP, the Borrower or any Subsidiary of the Borrower that is incurred after the date hereof and that does not have any amortization payment due or maturity date occurring sooner than six months after the last day of the Term Out Period (as defined in the Senior Credit Agreement), determined on the assumption that the Term Out Period will become effective under the Senior Credit Agreement on June 29, 2012.  As used above the Term Out Period shall be determined on the basis of the Senior Credit Agreement as in effect on the date hereof without giving effect to any amendment, supplement or other modification thereto not consented to by the Lender.

“ Senior Agent ” shall mean Wachovia Bank, National Association.

 “ Senior Credit Agreement ” shall mean the Amended and Restated Revolving Credit Agreement, dated as of June 29, 2006, by and among the Borrower, Texas Gas Transmission, LLC, Gulf South Pipeline Company, L.P., the several lenders from time to time party thereto, and the Senior Agent, as administrative agent, as amended by (x) Amendment No. 1 thereto, dated as of April 2, 2007 and (y) Amendment No. 2 thereto, dated as of November 27, 2007, and as the same may be further amended, restated, amended and restated, supplemented, modified, refunded, replaced or refinanced from time to time.

“ Senior Debt ” shall mean the “Obligations”, as such term is defined in the Senior Credit Agreement.

 “ Senior Loan Documents ” shall mean the “Loan Documents”, as such term is defined in the Senior Credit Agreement.

“ Subordinated Loan ” shall have the meaning set forth in Section 2.1 .

“ Subordinated Loan Commitment ” shall mean the obligation of the Lender to make  Subordinated Loans hereunder in an aggregate principal amount not exceeding $200,000,000.

“ Subordinated Loan Documents ” shall mean, collectively, this Agreement, the Subordination Agreement, the Subordinated Note, and each Notice of Borrowing.

“ Subordinated Loan Interest Rate ” shall mean 8.00% per annum.

“ Subordinated Note ” shall mean a promissory note of the Borrower payable to the order of the Lender in the principal amount of the Subordinated Loan Commitment, in substantially the form of Exhibit A .

“ Subordination Agreement ” shall mean that certain Subordination Agreement, dated as of May 1, 2009, among the Lender, the Senior Agent, and the Borrower, as the same may be amended, restated, amended and restated, supplemented, modified, refunded, replaced or refinanced from time to time.

“ Subsidiary ” shall mean as to any Person, a corporation, partnership, limited liability company or other entity of which shares of stock or other ownership interests having ordinary voting power (other than stock or such other ownership interests having such power only by reason of the happening of a contingency) to elect a majority of the Board of Directors or other managers of such corporation, partnership or other entity are at the time owned, or the management of which is otherwise controlled, directly or indirectly through one or more intermediaries, or both, by such Person.

Section 1.2   Other Definitional Provisions

(a)   .  Unless otherwise specified therein, all terms defined in this Agreement shall have the defined meanings when used in the other Subordinated Loan Documents or any certificate or other document made or delivered pursuant hereto or thereto.

(b)   The words “ hereof ”, “ herein ” and “ hereunder ” and words of similar import when used in this Agreement shall refer to this Agreement as a whole and not to any particular provision of this Agreement, and Section, Schedule and Exhibit references are to this Agreement unless otherwise specified.

(c)   The meanings given to terms defined herein shall be equally applicable to both the singular and plural forms of such terms.

(d)   The terms “Lender” shall include, without limitation, its successors.

Section 1.3   Accounting Terms and Principles .

(a)   Except as set forth below, all accounting terms not specifically defined herein shall be construed in conformity with GAAP and all accounting determinations required to be made pursuant hereto shall, unless expressly otherwise provided herein, be made in conformity with GAAP.

(b)   If any change in the accounting principles used in the preparation of the most recent financial statements is hereafter required or permitted by the rules, regulations, pronouncements and opinions of the Financial Accounting Standards Board or the American Institute of Certified Public Accountants (or any successors thereto) and such change is adopted by the Borrower with the agreement of the Borrower’s independent certified public accountants and results in a change in any calculations that would not have resulted had such accounting change not occurred, the parties hereto agree to enter into negotiations in order to amend such provisions so as to equitably reflect such change such that the