NorthWestern Energy Group, Inc.

Overview

NorthWestern Energy Group, Inc. is a U.S. regulated electric and natural-gas utility. Its businesses provide electricity and natural-gas services, including gas production, storage, transmission and distribution, to approximately 850,300 customers. The company describes its purpose as providing essential energy infrastructure and services that enrich lives and empower communities, with an emphasis on safe, reliable service.[1][2]

Its operations are concentrated in Montana, South Dakota and Nebraska, as well as Yellowstone National Park; the company’s reported service territory is domestic.[1][3] In 2025, operating revenues were approximately $1.61 billion, and the company reported 1,667 employees.[4][5] [1]+4

Products & services

NorthWestern Energy’s customer offerings are regulated electric and natural-gas utility services rather than separately branded products. Its electric service includes retail supply and transmission; South Dakota retail tariffs include dual-fuel, interruptible, and special all-electric-heating rates for residential, commercial, and industrial customers.[6][7] Its natural-gas services include production, storage, transmission, and distribution in Montana, South Dakota, and Nebraska, with gas delivered to retail customers and transportation service provided to third-party marketers and large end users.[8][9] In South Dakota, transportation service includes daily customer nominations, usage monitoring, and balancing against supply agreements.[6]

For the year ended December 31, 2025, electric and gas segment operating revenues were $1,269.956 million and $340.603 million, respectively—about 78.9% and 21.1% of total segment operating revenue.[10] For the six months ended June 30, 2026, the corresponding revenues were $686.308 million electric and $203.861 million gas, or about 77.1% and 22.9% of the combined total.[11] These figures represent segment revenues, not sales of distinct product lines. [6]+5

Geographic presence

NorthWestern Energy Group’s operating footprint is concentrated in Montana, South Dakota, and Nebraska, with electric service also extending into Yellowstone National Park. Its official service-area information describes electric operations in western and central Montana, eastern South Dakota, and Yellowstone National Park; natural-gas service covers those areas as well as communities in Nebraska.[12][13]

The 2025 annual report gives specific gas-service scale: Montana distribution served about 249,400 customers in 123 communities, South Dakota about 51,200 customers in 82 communities, and Nebraska about 43,400 customers in four communities.[14][9] Company-published coverage details also include electric service in 25 eastern South Dakota counties, natural-gas service in 20 South Dakota counties, and natural-gas service in three Nebraska counties.[15]

The 2025 report provides state-level revenue figures by customer class rather than a consolidated state revenue percentage: residential electric revenue included $406.643 million in Montana and $77.894 million in South Dakota; residential gas revenue included $120.830 million in Montana, $28.948 million in South Dakota, and $25.733 million in Nebraska.[16][17] The listed principal executive office is at 3010 W. 69th Street, Sioux Falls, South Dakota.[18] [12]+12

Business segments

NorthWestern Energy Group reports two business segments: Electric and Gas. Electric covers regulated electric utility operations in Montana and South Dakota; Gas covers regulated gas utility operations in Montana, South Dakota, and Nebraska.[7]

The Electric segment includes regulated generation, transmission, and distribution; Gas includes regulated production, storage, transmission, and distribution.[19][8] In FY2025, Electric contributed approximately 78.9% of operating revenues and Gas 21.1%.[10] In the first half of 2026, their respective shares were approximately 77.1% and 22.9%.[11] [7]+8

Company history

NorthWestern’s history dates to 1923, when Northwestern Public Service Company was formed by the merger of two Nebraska and two South Dakota electric utilities. Over the following years it acquired local energy companies across the region; in 1941 it sold its Nebraska electric utility holdings and used the proceeds to expand its natural-gas operations in three Nebraska cities.[20]

The company adopted the name NorthWestern Corporation in 1998. Its 2002 purchase of Montana Power Company’s transmission and distribution system marked a major expansion into Montana. In 2023, NorthWestern Energy Group, Inc. became the holding-company parent of NorthWestern Corporation. In 2026, the company further expanded its generation portfolio by acquiring additional ownership interests in Colstrip Units 3 and 4.[21]+3 [22]+4

Sources

• NorthWestern Energy Group, Inc. — Full financial report (2026 Q 2)
  8 citations

  [1][2][3][8][11][19][23][24]
• NorthWestern Energy Group, Inc. — Full financial report (2025 Y)
  10 citations

  [4][6][7][9][10][12][14][16][17][18]
• www2.northwesternenergy.com[5]
• northwesternenergy.com[13]
• www.northwesternenergy.com[15]
• northwesternenergy.com[20]
• northwesternenergy.com[21]
• NorthWestern Energy Group, Inc. — Full financial report (2024 Y)[22]