NorthWestern Corporation, doing business as NorthWestern Energy, provides electricity and natural gas to residential, commercial, and various industrial customers. The company operates through three segments: Electric Utility Operations; Natural Gas Utility Operations; and Other. It generates, purchases, transmits, and distributes electricity; and produces, purchases, stores, transmits, and distributes natural gas, as well as owns municipal franchises to provide natural gas service in the communities. The company operates 6,597 miles of electric transmission and 18,534 miles of electric distribution lines with approximately 121 transmission and distribution substations; and 2,235 miles of natural gas transmission and 5,099 miles of natural gas distribution lines with approximately 135 city gate stations in Montana. It also operates 1,308 miles of electric transmission and 2,342 miles of electric distribution lines in South Dakota with approximately 121 transmission and distribution substations; and 55 miles of natural gas transmission and 2,545 miles of natural gas distribution lines in South Dakota and Nebraska. The company serves approximately 764,200 customers in Montana, South Dakota, Nebraska, and Yellowstone National Park. NorthWestern Corporation was incorporated in 1923 and is based in Sioux Falls, South Dakota.