Youngsville is a city in Lafayette Parish, Louisiana, United States, and is part of the Lafayette metropolitan statistical area. The population was 8,105 at the 2010 U.S. census, and 15,929 at the 2020 United States census. Youngsville was the birthplace of Louisiana businessman and politician Dudley J. LeBlanc, the entrepreneur of the Hadacol fortune of the 1950s. Bernard LeBas of Ville Platte has represented Evangeline and St. Landry parishes in the Louisiana House of Representatives since 2008.