Jefferson

Formed January 1, 1819 (18^th county)

Jefferson County (37,118), Mount Vernon (14,598)

A multi-angled masonry and concrete Art Deco style courthouse was built in 1939.  It replaced an 1889 classic courthouse in Mount Vernon which is the only county seat.  It is located on 10^th, Main, 9^th, and Broadway streets.  Main Street is westbound Illinois State Highway 15 in this part of the city.  William R. McCoy is the architect.  The grounds feature a canon and veteran memorials.  The county was created on January 1, 1819 from White, Edwards, and Franklin counties as the 18^th county.  President Thomas Jefferson is the namesake for the county.  Mount Vernon was named for President George Washington’s estate. 

Jefferson County government consists of a sheriff and 13 Commissioners.  Twenty-one Circuit Court Judges serve Jefferson, Crawford, Edwards, Franklin, Gallatin, Hamilton, Hardin, Lawrence, Richland, Wabash, Wayne, and White counties.  The county is the south-central part of the state.  Saint Louis, Missouri is northwest and Evansville, Indiana is southeast of the county.  The county center is 7.2 miles South-Southeast of Mount Vernon nearer Bonnie.  The county is surrounded clockwise by Marion, Wayne, Hamilton, Franklin, Perry, and Washington counties. 

The area of the county is 571 square miles.  It is 41 out of 102 in the state.  It ranks 37 out of 102 in population in the state.  It has a density of 65.0 persons per square mile making it 38 out of 102 in the state.  Jefferson County has 51.9% of its population in its incorporated areas.  Interstate Highway 57 crosses the county north to south from Marion County to Franklin County.  Interstate Highway 64 goes east to west from Wayne County to Washington County.  The county is a rectangle.  Mount Vernon is located near the center of the county.  Mount Vernon is the county seat and the largest city.  It is 39.3% of the county population.  This county is in the Mount Vernon Micropolitan Statistical Area.

Centralia