FOURTH SUPPLEMENTAL INDENTURE

Exhibit 4.1

NOBLE DRILLING CORPORATION,
as Issuer,

NOBLE DRILLING HOLDING LLC,
as Co-Issuer,

NOBLE DRILLING SERVICES 1 LLC,
as Co-Issuer,

NOBLE HOLDING (U.S.) CORPORATION,
as Guarantor,
and

NOBLE CORPORATION,
as Guarantor,
and

THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A.,
as Trustee

FOURTH SUPPLEMENTAL INDENTURE

Dated as of September 25, 2009

to

INDENTURE
Dated as of March 1, 1999, as previously amended and supplemented

7.50% SENIOR NOTES DUE 2019

           FOURTH SUPPLEMENTAL INDENTURE dated as of September 25, 2009, among NOBLE DRILLING CORPORATION, a corporation duly organized and existing under the laws of the State of Delaware (“ Noble Drilling ”), NOBLE DRILLING HOLDING LLC, a limited liability company duly organized and existing under the laws of the State of Delaware (“ Drilling Holding ,” and collectively with Noble Drilling, the “ Company ” or “ Companies ”), NOBLE DRILLING SERVICES 1 LLC, a limited liability company duly organized and existing under the laws of the State of Delaware (“ NDS1 ”), NOBLE HOLDING (U.S.) CORPORATION, a corporation duly organized and existing under the laws of the State of Delaware (“ Holding ”), and NOBLE CORPORATION, a Cayman Islands exempted company limited by shares (collectively with Holding, the “ Guarantors ”), and THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A., a national banking association, successor by merger to JPMorgan Chase Bank, National Association (formerly Chase Bank of Texas, National Association), as trustee (the “ Trustee ”).

R E C I T A L S:

          WHEREAS, Noble Drilling has previously executed and delivered to the Trustee an indenture dated as of March 1, 1999 (as supplemented by the First Supplemental Indenture thereto dated as of March 16, 1999, the Second Supplemental Indenture thereto dated as of April 30, 2002 and the Third Supplemental Indenture thereto dated as of December 20, 2005, the “ Supplemented Indenture ”) providing for the issuance by Noble Drilling from time to time of its unsecured senior debt securities (the “ Securities ”), issuable in one or more series;

          WHEREAS, Noble Drilling has issued, and the Trustee has authenticated and delivered, a series of Securities designated “7.50% Senior Notes due 2019” (the “ Notes ”);

          WHEREAS, the Companies are the obligors with respect to the Notes and the Guarantors have guaranteed the due and punctual payment of the principal of, premium, if any, interest on, and all other amounts due under, the Notes;

          WHEREAS, as part of an internal reorganization, Noble Drilling intends to contribute, transfer, convey and assign on the date hereof to NDS1 assets (including equity interests in directly owned subsidiaries of Noble Drilling) representing all but three of the drilling rigs owned directly or indirectly by Noble Drilling (the “Asset Transfer”) in exchange for and in consideration of (i) an increase in Noble Drilling’s capital account balance in NDS1 and (ii) NDS1’s assumption of certain liabilities of Noble Drilling;

          WHEREAS, the Asset Transfer may be deemed a transfer of Noble Drilling’s properties and assets substantially as an entirety;

          WHEREAS, pursuant to Section 801 of the Supplemented Indenture, NDS1, as the transferee of all or substantially all of Noble Drilling’s properties and assets, is required to expressly assume, by an indenture supplemental to the Supplemented Indenture, the due and punctual payment of the principal of, premium, if any, and interest on, and any Additional Amounts with respect to, the Securities and the performance of Noble Drilling’s covenants and obligations under the Supplemented Indenture and the Securities;

          WHEREAS, Section 901 of the Supplemented Indenture provides that, without the consent of any Holders, Noble Drilling, when authorized by a Board Resolution, and the Trustee, at any time and from time to time, may enter into one or more indentures supplemental to the Supplemented Indenture to evidence the succession of another Person to Noble Drilling and the assumption by any such successor of the covenants of Noble Drilling in the Supplemented Indenture and in the Securities;

          WHEREAS, the Companies, NDS1 and the Guarantors, pursuant to the foregoing authority, propose to amend and supplement the Supplemented Indenture in certain respects to evidence the succession of NDS1 to Noble Drilling and the assumption by NDS1 of the covenants and obligations of Noble Drilling in the Supplemented Indenture and the Securities; and

          WHEREAS, all things necessary to make this F