Founding: Johnson County was founded on Aug. 25, 1855, as one of the first 33 counties recognized by the Legislative Act of 1855 in the Territory of Kansas. Statehood was granted six years later as Kansas became the 34th state on Jan. 29, 1861. The state now has 105 counties.
Namesake: Named after the Rev. Thomas Johnson, a Methodist minister who established the Shawnee Indian Mission in 1829. The mission, a National and Kansas Historic Site, is located in the city of Fairway.
County Seat: Olathe.
Johnson County Government: Organized on Sept. 7, 1857.
20 Cities: Overland Park, Olathe, Shawnee, Leawood, Lenexa, Mission, Mission Hills, Mission Woods, Merriam, Lake Quivira, Fairway, Westwood, Westwood Hills, Prairie Village, Roeland Park, De Soto, Spring Hill, Gardner, Edgerton, and Bonner Springs.
Six Public School Districts: Shawnee Mission, Olathe, Blue Valley, Spring Hill, Gardner-Edgerton, and De Soto. Student enrollment (K-12) totaled more than 88,500 for the 2011-2012 school year. That’s more than the individual populations of 100 counties in Kansas.
Seven Townships: Lexington, Olathe, McCamish, Spring Hill, Gardner, Oxford, and Aubry.
Size: 477 square miles or approximately 307,200 acres.
Urban land: Approximately 59 percent of Johnson County has been incorporated into city limits.
Rural land: Approximately 41 percent of Johnson County remains unincorporated/rural areas.
Median age: 36.5
Median Household Income (Estimated 2012): $74,761
Population: Johnson County is the most populous county in the state of Kansas.