St. Charles Parish is a parish located in the U.S. state of Louisiana. At the 2020 census, its population was 52,549. The parish seat is Hahnville and the most populous community is Luling. The parish was established in 1807, following the Louisiana Purchase by the United States in 1803. It was originally part of the German Coast, an area along the east bank of the Mississippi River that was settled by numerous German pioneers in the 1720s.