Vincennes is a city in, and the county seat of, Knox County, Indiana, United States. It is located on the lower Wabash River in the southwe…Vincennes is a city in, and the county seat of, Knox County, Indiana, United States. It is located on the lower Wabash River in the southwestern part of the state, nearly halfway between Evansville and Terre Haute. It was founded in 1732 by French fur traders, including the namesake François-Marie Bissot, Sieur de Vincennes. It is the oldest continually inhabited European settlement in Indiana and was its longest serving territorial capital. It is one of the oldest settlements west of the Appalachians. The population was 16,759 at the 2020 census.