Cavalier is the largest city in Pembina County, North Dakota, United States. It is the county seat of Pembina County. The population was 1,246 at the 2020 census. Cavalier was founded in 1875 and became the county seat in 1911. Although they bear the same name, Cavalier is not located in nearby Cavalier County. The Tongue River flows past Cavalier and Cavalier Space Force Station is located near the city.