Exhibit 21.1

WEC ENERGY GROUP, INC.

SUBSIDIARIES AS OF DECEMBER 31, 2017

The following table includes the subsidiaries of WEC Energy Group, a diversified holding company incorporated in the state of Wisconsin, as well as the percent of ownership, as of December 31, 2017:

Subsidiary *	State of Incorporation or Organization	Percent Ownership
Wisconsin Electric Power Company	Wisconsin	100%
Bostco LLC	Wisconsin	100%
Wisconsin Gas LLC	Wisconsin	100%
ATC Holding LLC	Wisconsin	100%
ATC Development Manager, Inc.	Delaware	75.17%
ATC Holdco, LLC	Delaware	75.17%
ATC Management Inc.	Wisconsin	26.24%
American Transmission Company LLC	Wisconsin	26.24%
Bluewater Natural Gas Holding, LLC	Delaware	100%
Bluewater Gas Storage, LLC	Delaware	100%
BGS Kimball Gas Storage, LLC	Delaware	100%
W.E. Power, LLC	Wisconsin	100%
Elm Road Generating Station Supercritical, LLC	Wisconsin	100%
Elm Road Services, LLC	Wisconsin	100%
Port Washington Generating Station, LLC	Wisconsin	100%
Wisvest LLC	Wisconsin	100%
Wispark LLC	Wisconsin	100%
Wisconsin Energy Capital Corporation	Wisconsin	100%
WEC Business Services LLC	Delaware	100%
WEC Investments, LLC	Delaware	100%
Upper Michigan Energy Resources Corporation	Michigan	100%
Integrys Holding, Inc.	Wisconsin	100%
Wisconsin Public Service Corporation	Wisconsin	100%
Wisconsin Valley Improvement Company	Wisconsin	27%
Wisconsin River Power Company	Wisconsin	50%
WPS Investments, LLC	Wisconsin	88%
American Transmission Company LLC	Wisconsin	34%
UMERC 2018 Merger Corp.	Wisconsin	100%
ATC Management Inc.	Wisconsin	34.07%
WPS Investments, LLC	Wisconsin	12%
Michigan Gas Utilities Corporation	Delaware	100%
Minnesota Energy Resources Corporation	Delaware	100%
Peoples Energy, LLC	Delaware	100%
The Peoples Gas Light and Coke Company	Illinois	100%
North Shore Gas Company	Illinois	100%
Peoples Energy Ventures, LLC	Delaware	100%
WPS Power Development, LLC	Wisconsin	100%
WPS Visions, Inc.	Wisconsin	100%
Penvest, Inc.	Michigan	100%

* Omits the names of certain subsidiaries, which if considered in the aggregate as a single subsidiary, would not constitute a "significant subsidiary" as of December 31, 2017. Indirectly owned subsidiaries are listed under the subsidiaries through which WEC Energy Group, Inc. holds ownership.