MDU Resources Group is a diversified natural resources company that provides value-added natural resource products and related services to customers in the United States. The company was founded in 1924 and is headquartered in Bismarck, North Dakota. MDU Resources Group's businesses include regulated electric and natural gas utilities, construction materials and services, and exploration and production of oil and natural gas. The company's electric and natural gas utilities serve customers in Montana, North Dakota, South Dakota, and Wyoming. MDU Resources Group's construction materials and services businesses provide construction materials and contracting services to customers in the United States. The company's exploration and production business explores for and produces oil and natural gas in the United States.