Here are some links to other popular sites:

 

Illinois State Genealogical Society

Illinois State Historical Society

Illinois Death Certificates Database

Illinois Death Index Pre-1916

Illinois Marriage Index 1763-1900

Illinois Regional Archives Depository (IRAD) System

Illinois Soldiers' & Sailors' Home Residents 1887-1916

Illinois County Boundaries

Genealogy Trails: Jackson County Illinois

Ancestry

Family Search

Find A Grave

Fold 3 Military Records