Mandan, Hidatsa, and Arikara Nation in the context of Treaty of Fort Laramie (1851)

North Dakota ( /dəˈkoʊtə/ də-KOH-tə) is a U.S. state in the Upper Midwest, named after the indigenous Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minnesota to the east, South Dakota to the south, and Montana to the west. North Dakota is part of the Great Plains region, characterized by broad prairies, steppe, temperate savanna, badlands, and farmland. North Dakota is the 19th-largest state by area, but with a population of just under 800,000, the fourth-least populous and fourth-least densely populated. The state capital is Bismarck and the most populous city is Fargo, which accounts for nearly a fifth of the state's population; both cities are among the fastest-growing in the U.S., although half of North Dakotans live in rural areas.

What is now North Dakota was inhabited for thousands of years by various Native American tribes, including the Mandan, Hidatsa, and Arikara along the Missouri River; the Ojibwe and Cree in the northeast; and several Sioux groups (the Nakota, Dakota, and Lakota) in the rest of the state. European explorers and traders first arrived in the early 18th century, mostly in pursuit of furs.

The Arikara (/əˈrɪkərə/ ə-RICK-ə-rə), also known as Sahnish, Arikaree, Ree, or Hundi, are a tribe of Native Americans in North Dakota and South Dakota. Today, they are enrolled with the Mandan and the Hidatsa as the federally recognized tribe known as the Mandan, Hidatsa, and Arikara Nation.

The Hidatsa (/hɪˈdɑːtsə/ hih-DOT-sə) are a Siouan people. They are enrolled in the federally recognized Three Affiliated Tribes of the Fort Berthold Reservation in North Dakota. Their language is related to that of the Crow, and they are sometimes considered a parent tribe to the modern Crow in Montana.

The Mandan (/ˈmæn.dæn/) are a Native American tribe of the Great Plains who have lived for centuries primarily in what is now North Dakota. They are enrolled in the Three Affiliated Tribes of the Fort Berthold Reservation. About half of the Mandan still reside in the area of the reservation; the rest reside around the United States and in Canada.

The Mandan historically lived along both banks of the Upper Missouri River and two of its tributaries—the Heart and Knife rivers—in present-day North and South Dakota. Speakers of Mandan, a Siouan language, they developed a settled, agrarian culture. They established permanent villages featuring large, round, earth lodges, some 40 feet (12 m) in diameter, surrounding a central plaza. Matrilineal families lived in the lodges. The Mandan were a great trading nation, trading especially their large corn surpluses with other tribes in exchange for bison meat and fat. Food was the primary item, but they also traded for horses, guns, and other trade goods.