MDU Resources Group, Inc. engages in the regulated energy delivery, and construction materials and services businesses in the United States. The company's Electric segment generates, transmits, and distributes electricity for residential, commercial, industrial, and municipal customers in Montana, North Dakota, South Dakota, and Wyoming, as well as operates 3,500 miles of transmission lines and 4,800 miles of distribution lines. Its Natural Gas Distribution segment distributes natural gas for residential, commercial, and industrial customers in Idaho, Minnesota, Montana, North Dakota, Oregon, South Dakota, Washington, and Wyoming; and offers supply-related value-added services.