|                                                                                                               |                                                | Exhibit                21                                                                                                                                           |
|--------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Affiliates                and Subsidiaries of Wisconsin Public Service CorporationDecember                31, 2007 |
|                                                                                                               |
|                                                                                                               |                                                |                                                                                                                                                                |
|                                                                                                               | Wisconsin                Public Service Corporation |
|                                                                                                               |                                                | WPS                Leasing,                Inc.                                                                                                                     |
|                                                                                                               |                                                | Wisconsin                Valley Improvement Company (27.1% ownership)                                                                                               |
|                                                                                                               |                                                | Wisconsin                River Power Company (50% ownership)                                                                                                        |
|                                                                                                               |                                                | WPS                Investments, LLC (approximately 17.3% ownership)                                                                                                 |
|                                                                                                               |                                                |                                                                                                                                                                | American                Transmission Company LLC (approximately 34.54% ownership) |
|                                                                                                               |                                                | ATC                Management                Inc. (32.58% ownership)                                                                                                |
|                                                                                                               |                                                |
|                                                                                                               |                                                | 100%                owned                unless noted otherwise.  All of these affiliates and                subsidiaries are formed under Wisconsin law. |

----