NorthWestern Corporation, doing business as NorthWestern Energy, provides electricity and natural gas to residential, commercial, and industrial customers. The company operates through Electric Operations and Natural Gas Operations segments. It generates, 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's natural gas transmission system covers approximately 4,810 miles of pipeline. It serves approximately 734,800 customers in Montana, South Dakota, and Nebraska, the United States. NorthWestern Corporation was founded in 1923 and is based in Sioux Falls, South Dakota.