Tensas Parish is a parish located in the northeastern section of the State of Louisiana; its eastern border is the Mississippi River. As of the 2020 census, the population was 4,147. It is the least populated parish in Louisiana. The parish seat is St. Joseph. The name Tensas is derived from the historic indigenous Taensa people. The parish was founded in 1843 following Indian Removal. The parish was developed for cotton agriculture, which dominated the economy through the early 20th century.