Williamson County is located in the southern part of Illinois and is part of the Metro East region. It is bordered by Jackson County to the north, Union County to the east, Saline County to the south, and Franklin County to the west. The county seat is Marion. The county was formed in 1839.

The county government is composed of a board of commissioners, a county clerk, a treasurer, a sheriff, and a state's attorney. The county is divided into 16 townships, and there are several unincorporated communities.

The county is home to several state parks, including Giant City State Park, Ferne Clyffe State Park, and Trail of Tears State Forest. It is also home to several wineries and vineyards, as well as the Shawnee National Forest.

The economy of Williamson County is largely based on agriculture, with corn, soybeans, and wheat being the main crops. The county also has a strong manufacturing sector, with several automotive and aerospace companies located in the area.

For the most up-to-date and in-depth information, please check the public records links below.