The Peoria County Genealogical Society, established in 1973, celebrates 50 years in 2023.

The first organizing meetings were held in the spring of 1973 establishing the Peoria Genealogical Society with by-laws, officers and 75 charter members by the end of June 1973. The first year of existence proved to be a busy one with over 130 new members from all over the nation and volunteer led projects such as reading cemeteries in Peoria and Tazewell Counties, surname index, and sponsorship of the reprint of the 1873 Peoria County Atlas.  The first issue of the Prairie Roots magazine was published in the Spring of 1974 and four times a year until 2010 when Prairie Roots magazine became a semi-annual publication. The society name was changed to the Peoria County Genealogical Society in 1990. The membership in 2015 boasts 250 individuals, societies, and libraries.

Holdings of the Peoria County Genealogical Society were initially located in the Flanagan House along with the Peoria Historical Society’s library. The collection was moved to its current location at the Peoria Public Library, downtown branch in the spring of 1976. When the library was being renovated in 2010, the complete genealogy and Peoria history collection was moved to the WTVP building on State Street in Peoria.  The collection was moved back to the Local History & Genealogy Department at the main downtown library on the lower level.