Black Hills Corporation Announces Schedule for First Quarter 2007
Earnings Release and Conference Call

For Information Contact: Mark T. Thies, Executive Vice President; Dale T. Jahr, Director, Investor Relations

RAPID CITY, SD—April 20, 2007—Black Hills Corporation (NYSE: BKH) will issue a press release regarding financial results of the first quarter of 2007 on Thursday, April 26, 2007.

In conjunction with this release, the Company will hold a conference call on Friday, April 27, 2007 beginning at 11:00 a.m. Eastern Time to discuss details regarding recent results. The conference call will be open to the public. The call can be accessed by dialing, toll-free, (800) 762-6568. When prompted, indicate that you wish to participate in the “Black Hills Conference Call."

A replay of the conference call will be available through May 4, 2007 by dialing (800) 475-6701 (USA) or (320) 365-3844 (international). The access code is 871680.

ABOUT BLACK HILLS CORPORATION
Black Hills Corporation is an integrated energy company. Our retail businesses are Black Hills Power, an electric utility serving western South Dakota, northeastern Wyoming and southeastern Montana; and Cheyenne Light, Fuel & Power, an electric and gas distribution utility serving the Cheyenne, Wyoming vicinity. Black Hills Energy, the wholesale energy business unit, generates electricity, produces natural gas, oil and coal, and markets energy. More information is available at our Internet website: www.blackhillscorp.com.