Black Hills Corporation, through its subsidiaries, operates as an electric and natural gas utility company in the United States. It operates through four segments: Electric Utilities, Gas Utilities, Power Generation, and Mining. The Electric Utilities segment generates, transmits, and distributes electricity to approximately 216,000 electric customers in Colorado, South Dakota, and Wyoming, as well as provides electrical system construction services to large industrial customers. This segment owns 992 megawatts of generation capacity and 8,892 miles of electric transmission and distribution lines. The Gas Utilities segment distributes natural gas to approximately 1,083,000 natural gas utility customers in Arkansas, Colorado, Iowa, Kansas, Nebraska, and Wyoming. It also provides appliance repair services to residential customers; and constructs and maintains gas infrastructure facilities for gas transportation customers. This segment owns and operates approximately 4,774 miles of intrastate gas transmission pipelines; 41,838 miles of gas distribution mains and service lines; seven natural gas storage sites; and approximately 49,000 horsepower of compression and 560 miles of gathering lines. The Power Generation segment produces electric power through wind, natural gas, and coal-fired generating plants; and sells the electric capacity and energy primarily to utilities under long-term contracts. The Mining segment produces coal at its coal mine located near Gillette, Wyoming; and sells the coal to electric generation facilities. Black Hills Corporation was incorporated in 1941 and is headquartered in Rapid City, South Dakota.