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| Delaware                                                      | 20-5464059                          |
|---------------------------------------------------------------|-------------------------------------|
| (State or other jurisdiction ofincorporation or organization) | (I.R.S. EmployerIdentification No.) |

| 14 Philips Parkway, Montvale, NJ  07645          |
|------------------------------------------------------------|
| (Address of principal executive offices) (Zip code)        |
|                                                       |
| (800) 942-5550                                             |
| (Registrant’s telephone number, including area code) |

| Large accelerated filer     | o                                              | Accelerated filer               | o |
|-----------------------------|------------------------------------------------|---------------------------------|---|
| Non-accelerated filer  | o(Do not check if a smaller reporting company) | Smaller reporting company  | x |

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| EXHIBIT |   |                                                                                                                                                                                                                                                    |   |                                                                     |
|---------|--------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|--------------------------------------------------------------------------|
| NUMBER  |   | TITLE OF EXHIBIT                                                                                                                                                                                                                                        |   | METHOD OF FILING                                                         |
|    |   |                                                                                                                                                                                                                                                    |   |                                                                     |
| 3.1     |   | Articles of Formation of Ridgewood Energy U Fund, LLC dated August 28, 2006.                                                                                                                                                                       |   | Incorporated by reference to the Fund's Form 10 filed on April 26, 2007. |
|    |   |                                                                                                                                                                                                                                                    |   |                                                                     |
| 3.2     |   | Limited Liability Company Agreement between Ridgewood Energy Corporation and Investors of Ridgewood Energy U Fund, LLC dated October 1, 2006.                                                                                                           |   | Incorporated by reference to the Fund's Form 10 filed on April 26, 2007. |
|    |   |                                                                                                                                                                                                                                                    |   |                                                                     |
| 31.1    |   | Certification of Robert E. Swanson, Chief Executive Officer of the Fund, pursuant to Securities Exchange Act Rule 13a-14(a)                                                                                                                             |   | Filed herewith                                                           |
|    |   |                                                                                                                                                                                                                                                    |   |                                                                     |
| 31.2    |   | Certification of Kathleen P. McSherry, Chief Financial Officer of the Fund, pursuant to Securities Exchange Act Rule 13a-14(a)                                                                                                                          |   | Filed herewith                                                           |
|    |   |                                                                                                                                                                                                                                                    |   |                                                                     |
| 32      |   | Certifications pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of The Sarbanes-Oxley Act of 2002, signed by Robert E. Swanson, Chief Executive Officer of the Fund and Kathleen P. McSherry, Chief Financial Officer of the Fund |   | Filed herewith                                                           |
|    |   |                                                                                                                                                                                                                                                    |   |                                                                     |
| 99      |   | Report of Ryder Scott Company, L.P.                                                                                                                                                                                                                     |   | Filed herewith                                                           |

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|                              | RIDGEWOOD ENERGY U FUND, LLC |                                                           |
|-----------------------------------|------------------------------|----------------------------------------------------------------|
|                              |                         |                                                           |
|                              |                         |                                                           |   |
| Date:   August 23, 2010 | By:                          | /s/ ROBERT E. SWANSON       |   |
|                              |                         | Robert E. Swanson                                              |   |
|                              |                         | Chief Executive Officer                                        |   |
|                              |                         | (Principal Executive Officer)                                  |   |

| Signature                            | Capacity                                                                            | Date                         |
|--------------------------------------|-------------------------------------------------------------------------------------|------------------------------|
|                                 |                                                                                |    August 23, 2010 |
| /s/ ROBERT E. SWANSON                | Chief Executive Officer(Principal Executive Officer)                                |
| Robert E. Swanson                    |                                                                                |
|                                 |                                                                                |                         |
|                                 |                                                                                |                         |
| /s/ KATHLEEN P. MCSHERRY             | Executive Vice President and Chief Financial Officer (Principal Accounting Officer) | August 23, 2010              |
| Kathleen P. McSherry                 |                                                                                |
|                                 |                                                                                |                         |
| RIDGEWOOD ENERGY CORPORATION         |                                                                                |                         |
|                                 |                                                                                |                         |
| BY:  /s/ ROBERT E. SWANSON | Chief Executive Officer of Manager                                                  | August 23, 2010              |
| Robert E. Swanson                    |                                                                                |                         |
|                                 |                                                                                |                         |

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