Vernon Parish is a parish located in the U.S. state of Louisiana. As of the 2020 census, the population was 48,750. The parish seat and most populous municipality is Leesville. Bordered on the west by the Sabine River, the parish was founded in 1871 during the Reconstruction era. It was long a center of the timber industry, which harvested pine in the hills and bottomland hardwoods. Construction of a railway to the area in 1897 stimulated the marketing of lumber and businesses in the area.