It dates to before the emergence of the Arikara, Hidatsa, and Mandan as separate peoples, and has been designated as a National Historic Landmark.

Species of fish in the reservoir include walleye, northern pike, channel catfish, and smallmouth bass.

[4] Chinook salmon, native to the Pacific Northwest, are artificially maintained in Lake Oahe and are a popular target for anglers.

In 2016, a group from the Standing Rock Indian Reservation brought a petition to the U.S. Army Corps of Engineers (USACE) and sued for an injunction to stop the project.

On December 4, 2016, USACE denied the easement that "would allow the Dakota Access Pipeline to cross under Lake Oahe" and Jo-Ellen Darcy, the United States Assistant Secretary of the Army, "said she based her decision on a need to explore alternate routes for the Dakota Access Pipeline crossing".

[8] Darcy stated, "that the consideration of alternative routes would be best accomplished through an Environmental Impact Statement with full public input and analysis".

[8] Then-president Donald Trump soon thereafter issued "a memorandum and an executive order asking USACE to expedite its consideration of the company’s application for an easement to start construction".

[10] On February 9, 2017, the Cheyenne River Sioux filed the first legal challenge to the easement, citing an 1851 treaty and interference with the religious practices of the tribe.