Buying a home in Williamson County, Illinois doesn't have to be difficult - Homes.com makes home buying a breeze. With 856 homes for sale in Williamson County, Illinois, you can search by price, bedrooms, neighborhood, and even by property type. Search Williamson County homes for sale, foreclosures, MLS listings, and more. Make an informed decision with Williamson County school data, neighborhood information, find Williamson County real estate agents, and research home values in Williamson County, IL. Homes.com has everything you need but the house keys.