NorthWestern Energy Group, Inc., doing business as NorthWestern Energy, provides electricity and natural gas to residential, commercial, and various industrial customers. 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 6,596 miles of electric transmission and 18,794 miles of electric distribution lines with approximately 396 transmission and distribution substations; and 2,133 miles of natural gas transmission and 5,221 miles of natural gas distribution lines with approximately 135 city gate stations in Montana. It also operates 1,349 miles of electric transmission and 2,386 miles of electric distribution lines in South Dakota with approximately 123 transmission and distribution substations; and 55 miles of natural gas transmission, 1,796 miles of natural gas distribution lines in South Dakota, and 830 miles of natural gas distribution lines Nebraska. The company provides electricity and/or natural gas to approximately 787,000 customers in Montana, South Dakota, Nebraska, and Yellowstone National Park. NorthWestern Energy Group, Inc. was founded in 1923 and is based in Sioux Falls, South Dakota.