Fort Benton is a city in and the county seat of Chouteau County, Montana, United States. A portion of the city was designated as a National Historic Landmark District in 1961. Established in 1846, a full generation before the U.S. Civil War, Fort Benton is one of the oldest settlements in the American West; in contrast many other places—including large cities today—were settled in the late 1860s, 1870s, or 1880s.