Interior reasserts North Dakota’s claim to invaluable riverbed

By Michael Doyle | 03/17/2026 01:44 PM EDT

The department reversed a Biden administration ruling that the Mandan, Hidatsa and Arikara Nation owns the bed of the Missouri River where it flows through its reservation.

A pump jack extracts oil from beneath the ground near a lake.

A pump jack in May 2021 extracting oil from beneath the ground on the Fort Berthold Indian Reservation, with Lake Sakakawea in the background, east of New Town, North Dakota. Matthew Brown/AP

Control of a resource-rich North Dakota riverbed has once again slipped from tribal hands and gone to the state, in the latest turnaround of an Interior Department legal posture that changes with the political seasons.

Capping a yearlong review, Interior Solicitor William Doffermyre reversed the Biden administration’s ruling that the Mandan, Hidatsa and Arikara Nation owned the bed of the Missouri River where it flows through their reservation.

“I conclude the better interpretation of applicable law is that the original Riverbed, and its underlying minerals where the Missouri River flows through the Fort Berthold Indian Reservation, passed to the State upon its admission to the Union,” Doffermyre stated in a brief opinion dated March 12.

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The riverbed in question is beneath Lake Sakakawea, which was created in the 1950s when the Missouri River was held back by construction of the Garrison Dam. The lake is located within the 980,000-acre Fort Berthold Indian Reservation in west-central North Dakota.

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