Black Hills Corporation, through its subsidiaries, operates as an electric and natural gas utility company in the United States. The company operates in two segments: Electric Utilities and Gas Utilities. The Electric Utilities segment generates, transmits, and distributes electricity to approximately 225,000 electric utility customers in Colorado, Montana, South Dakota, and Wyoming; and owns and operates 1,394 megawatts of generation capacity and 9,106 miles of electric transmission and distribution lines. The Gas Utilities segment distributes natural gas to approximately 1,128,000 natural gas utility customers in Arkansas, Colorado, Iowa, Kansas, Nebraska, and Wyoming; owns and operates 4,648 miles of intrastate gas transmission pipelines; 44,524 miles of gas distribution mains and service lines; seven natural gas storage sites; and approximately 50,000 horsepower of compression and 516 miles of gathering lines. It also constructs and maintains customer owned 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, the company produces electric power through wind, natural gas, and coal-fired generating plants; and coal at its coal mine located near Gillette, Wyoming. Black Hills Corporation was incorporated in 1941 and is headquartered in Rapid City, South Dakota.