Jerseyville is a city in Jersey County, Illinois, United States. As of the 2010 U.S. census, the city had a total population of 8,465. It is the county seat of Jersey County, and is also the largest city in the county. The city's current mayor is Richard Perdun. According to the United States Census Bureau, the city has a total area of 4.4 square miles (11km2). None of it is covered by water.