Black Hills Corporation, through its subsidiaries, operates as an electric and natural gas utility company in the United States. It operates in two segments, Electric Utilities and Gas Utilities. The Electric Utilities segment generates, transmits, and distributes electricity to approximately 220,000 electric utility customers in Colorado, Montana, South Dakota, and Wyoming; and owns and operates 1,482 megawatts of generation capacity and 9,024 miles of electric transmission and distribution lines. The Gas Utilities segment distributes natural gas to approximately 1,107,000 natural gas utility customers in Arkansas, Colorado, Iowa, Kansas, Nebraska, and Wyoming; owns and operates 4,713 miles of intrastate gas transmission pipelines; 42,222 miles of gas distribution mains and service lines; seven natural gas storage sites; and approximately 50,000 horsepower of compression and 515 miles of gathering lines. The company also constructs and maintains gas infrastructure facilities for gas transportation customers; and provides appliance repair services to residential utility customers, as well as electrical system construction services to large industrial customers. In addition, it produces electric power through wind, natural gas, and coal-fired generating plants; and coal at its coal mine located near Gillette, Wyoming. The company was incorporated in 1941 and is headquartered in Rapid City, South Dakota.