Named after Thomas Jefferson, third President of the United States (1801-1809) and author of the Declaration of Independence. Established: March 26, 1819 County Seat: Mount Vernon
Related categories 1
ILGenWeb - Jefferson County
Online resource for Jefferson County family historians.
Jefferson County Data
Data from the US Department of Congress, Bureau of the Census.
Jefferson County IL Democrats
News and information about Democratic candidates, elected officials and events for the county, its townships and Illinois.
Last update:October 20, 2015 at 15:20:13 UTC