Williamson County, Illinois Genealogy Records

Which records survive from Williamson County, the years each set covers, and where to find them.

Formed
1839
County seat
Marion
Gallatin CountyHamilton CountyHardin CountyJackson CountyJefferson CountyJohnson CountyPerry CountyPope CountySaline CountyUnion CountyWashington CountyWayne CountyWhite CountyFranklin CountyWilliamson CountyHardinJacksonPerrySalineFranklinWilliamson
Williamson CountyParent county (search here for earlier records)Today's boundaries ยท U.S. Census Bureau

Records that survive

These are the record series from Williamson County held by the Illinois Regional Archives Depository (IRAD) system, with the earliest and latest years. A span can include gaps. They include county, township and city records.

The IRAD database lists no records for Williamson County here; ask the county clerk and the clerk of the circuit court what survives.

Search the IRAD database for this county

Source: Illinois State Archives, Local Government Records Database (choose the county to see every series and its accession number). Contact the depository before you visit. Illinois began statewide registration of births and deaths in 1916.

Where to find the records

  • Williamson County official website

    Hours, addresses and phone numbers for the county clerk, the recorder of deeds and the clerk of the circuit court, and any online record search the county offers.

  • The county clerk

    Births, deaths and marriages registered in the county.

  • The recorder of deeds

    Deeds, mortgages and other land records (in some counties the county clerk is also the recorder).

  • The clerk of the circuit court

    Probate (wills and estates), divorces and civil and criminal cases.

  • The Illinois State Archives

    In Springfield, with older county records at its regional depositories (IRAD) on university campuses.

  • Illinois Regional Archives Depository (IRAD) systemfree

    The State Archives' regional depositories, which hold older county, township and city records; search its Local Government Records Database by county.

  • FamilySearch Catalogfree

    Search by place for "Illinois, Williamson" to find filmed and digitized records, many viewable free online with a FamilySearch account.

Offices change their hours and access rules; call before you visit.

Boundaries and parent counties

Formed from: Franklin County

Check the parent county for earlier records: Franklin County

UnionJohnsonGallatinPopeHamiltonJeffersonWashingtonJacksonPerryFranklinWilliamsonWilliamsonFranklinGallatinHamiltonJacksonPerry
Williamson as created in 1839Where its land was the day beforeToday's boundaryBoundaries: Newberry Library, Atlas of Historical County Boundaries

Records stay with the county that created them. If your ancestor lived here before 1839, search the parent county. The Atlas of Historical County Boundaries shows each boundary change.

Research tip

Illinois began statewide registration of births and deaths in 1916; counties kept registers earlier, often from 1877 or 1878. The Illinois Statewide Marriage Index, from the State Archives, covers many marriages from 1763 to 1900.