Exhibit 21.1
Name of Subsidiary | Jurisdiction of Incorporation or Organization | Assumed Names Under Which Subsidiary Does Business |
| ATLAS ENERGY OPERATING COMPANY, LLC | Delaware | None |
| ATLAS ENERGY FINANCE CORP. | Delaware | None |
| AER PIPELINE CONSTRUCTION, INC. | Delaware | None |
| AIC, LLC | Delaware | None |
| ANTHEM SECURITIES, INC. | Pennsylvania | None |
| ATLAS AMERICA, LLC | Pennsylvania | Atlas Energy Resources, LLC (in Ohio) Atlas Energy Resources (in West Virginia and Tennessee) |
| ATLAS ENERGY MICHIGAN, LLC | Delaware | Atlas Energy Resources (in Michigan) |
| ATLAS ENERGY OHIO, LLC | Ohio | None |
| ATLAS GAS & OIL COMPANY, LLC | Michigan | None |
| ATLAS NOBLE, LLC | Delaware | None |
| ATLAS RESOURCES, LLC | Pennsylvania | Atlas Energy Resources (in West Virginia and Tennessee) |
| REI-NY, LLC | Delaware | None |
| RESOURCE ENERGY, LLC | Delaware | Atlas Energy Resources (in New York) |
| RESOURCE WELL SERVICES, LLC | Delaware | None |
| VIKING RESOURCES, LLC | Pennsylvania | None |
| WESTSIDE PIPELINE COMPANY, LLC | Michigan | None |