The Williamson County Historical Society operates a great research library in their Jail Museum at 105 S. Van Buren Street in Marion.
They are open from 9 a.m. to 3 p.m. on Thursdays, as well as open until 8 p.m. on the third Thursday of each month. Tours of the museum are given on Thursdays with the last tour starting at 2 p.m.
In Herrin the expanded city library has developed a great local history room under the guidance of retired high school librarian Linda Banks. The library honored her last Sunday by naming the room the after her.
The Herrin City Library is located at 120 N. 13th St., one block east of Park Avenue which is Route 148.
The Frankfort Area Genealogy Society also operates another major local research library in the old Logan School in Frankfort Heights on the east side of West Frankfort at 2000 E. St. Louis St.
It's open on Wednesdays and Thursdays from 9 a.m. to 3 p.m.
Although located in Franklin County this museum and library includes a lot of information about Williamson County, particularly the north portion the county. Historically, Williamson County was a part of Franklin from 1818 to 1839.
The genealogical collection of the Genealogy Society of Southern Illinois is available for researchers at the John A. Logan College library in Carterville.
Other good sites for research include the following:
- Morris Library, SIU-Carbondale
- Illinois Regional Archives Depository (IRAD), Carbondale
- Saline County Genealogy Society's Library, Harrisburg City Hall (open weekday mornings)