NorthWestern Corp provides electricity and natural gas services in the Upper Midwest and Northwest of the U.S. in the states of Montana, South Dakota, Nebraska, and Yellowstone National Park. The primary segments of the company include Electric operations, which includes the generation, purchase, transmission and distribution of electricity, and Natural Gas operations, which includes the production, purchase, transmission, storage, and distribution of natural gas. The company uses thermal, wind, hydro, or renewable energy in varying quantities, depending on the location of the facilities, in order to generate power. The company derives the majority of retail electric utility revenue from commercial and residential sales.