Mandan, Hidatsa, & Arikara Nation

Mandan, Hidatsa, & Arikara Nation



404 Frontage Road
New Town, North Dakota 58763


Mark Fox, Chairman, 2018-2022


The constitution of the Mandan, Hidatsa and Arikara Nation was ratified in 1936 and established a democratic representative government. The Tribal Business Council is the governing body of the tribe and retains full legislative and executive authority. The Tribal Business Council consists of twelve council members, who represent the six segments of the Fort Berthold Reservation, and a chairman of the tribe; all council members serve two-year terms. The Tribal Business Council manages all tribal economic affairs and business interests, administers all tribal finances, and has authority over the sale, leasing, and development of tribal property. All land not allotted to tribal members is owned by the Tribal Business Council and subject to the improvements determined by the council or tribal members in a popular referendum. With the petition of 10 percent of tribal citizens, all Tribal Business Council resolutions and enactments are subject to a referendum vote. 

Congressional House Representation

Congressional House Representation:

Kelly Armstrong, Republican, At-Large District, 2018-2020

Congressional Senate Representation

Congressional Senate Representation:

John HoevenRepublican, 2016-2022

Kevin Cramer, Republican, 2018-2024

Tribal Enterprises



The Mandan, Hidatsa and Arikara Nation owns enterprises in oil and gas, travel, tourism, gaming, recreation, and solid waste. The tribe sits on the Bakken Oil Field, one of the largest oil and gas deposits in the United States. Currently the tribe is expanding oil and gas extraction operations and refining operations.


Missouri River Resources is a tribal energy company that oversees the development of the more than 13 billion barrels of oil under the Fort Berthold Reservation. The company also operates the Native American Petroleum Academy.
 Phone: (701) 627-3058

Thunder Butte Petroleum Services, Inc. was established in 2011 to oversee the development of refining capacity for the tribe. The company operates the MHA Clean Fuels Refinery and is currently constructing a new refinery with a capacity of 140,000 BBL.
 Phone: (701) 862-2560

Four Bears Casino and Lodge features more than 500 electronic games, a luxury lodge, RV park, lakeside cabins, three restaurants, a lounge, and a state-of-the-art event center. The property also includes a marina and yacht charters on Lake Sakakaewa.
 Phone: (800) 294-5454


The Mandan, Hidatsa and Arikara (Sahnish) tribes originate from the Missouri River region and occupy their homeland today. The Mandan and Hidatsa belong to the Siouan language group, while the Sahnish belong to the Caddoan language group; all are linked to the Eastern Woodlands cultural tradition. Originally inhabiting the woodlands region east of the Mississippi, the three tribes migrated to the Plains around 1,000 AD. In the nineteenth century, a devastating series of wars, epidemics, and droughts brought the Mandan, Hidatsa, and Arikara tribes together for survival. In 1870 the new homogenous entity, the Three Affiliated Tribes, saw the tribes’ lands substantially reduced from the land recognized in the 1851 Fort Laramie Treaty. In 1880 an executive order further diminished the reservation, which originally occupied 12 million acres in 1851, to the current borders of the Fort Berthold Reservation. However, the most devastating effects suffered by an Indian reservation occurred in the mid-twentieth century with the construction of the Garrison Dam. As part of the Pick-Sloan plan, the dam resulted in the dispossession of over 150,000 acres for construction, the loss of a quarter of the total reservation to reservoirs, and the relocation of nearly 80% of the reservation’s total population. The Garrison Dam destroyed 94% of the agricultural lands on the Fort Berthold Reservation.