You’ll find expert advice for discovering ancestors in all of FamilySearch’s free online resources—genealogy books, records, Family Tree, old photos, and more—in the Unofficial Guide to FamilySearch.org book and the FamilySearch.org Cheat Sheet.
1. Local Histories and Records
2. City Directories
3. Family Histories
4. Genealogical Society Publications
Our search on illinois genealogical society turned up results for county societies in Illinois. FamilySearch books suggested adding the word state to our search to find publications by the Illinois State Genealogical Society.