William Priestley was the third child and second son of Joseph Priestley and his wife Mary Wilkinson. He spent some time in France, before migrating to the US in 1793, taking the oath of citizenship on 8 October 1798. In 1801 he moved to Louisiana, with the intention of establishing a school in Point Coupee Parish. Some time between 1804 and 1807, William purchased a sugar plantation on the west bank of the Mississippi River.

Pointe Coupee Parish is a parish located in the U.S. state of Louisiana. As of the 2020 census, the population was 20,758. The parish seat is New Roads.