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. 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. The company's Pipeline segment provides natural gas transportation and underground storage services through a regulated pipeline system primarily in the Rocky Mountain and northern Great Plains regions and cathodic protection and other energy-related services. Its Construction Materials and Contracting segment mines, processes, and sells construction aggregates produces and sells asphalt mix and supplies ready-mixed concrete. This segment is also involved in the sale of cement, liquid asphalt, finished concrete products, and other building materials and related contracting services. The company's Construction Services segment designs, constructs, and maintains electrical and communication wiring and infrastructure, fire suppression systems, and mechanical piping and services and overhead and underground electrical distribution and transmission lines, substations, external lighting, traffic signalization, and gas pipelines, as well as engages in the utility excavation activities. This segment also manufactures and distributes transmission line construction equipment and constructs and maintains renewable energy projects. It serves manufacturing, commercial, industrial, institutional, and government customers, as well as utilities. The company was founded in 1924 and is headquartered in Bismarck, North Dakota.