Cavalier is a city in Pembina County, North Dakota in the United States. It is the county seat of Pembina County. The population was 1,537 at the 2000 census. Cavalier was founded in 1877 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 Air Force Station is located near the city.