A department of Johnson County government, the Johnson County Museum began as an all-volunteer organization in 1967. The original museum was housed in the former 1927 Greenwood School located in Shawnee, Kansas. The museum’s collections and facility grew over time and now include over 1 million photographs, 15,000 3-D artifacts, and 3,000 cu. ft. of archival material. Significant holdings include the Sun Newspapers photographic morgue from the mid-1980s - 1990s, a bound set of Tom Leather's Squire publications from the early 1960s - 2000s, and material from the Sunflower Ammunition Plant near De Soto. The museum has also built a significant collection documenting the suburban experience in Johnson County.
The museum offers long-term and changing exhibits, a speakers bureau, online resources for research, teacher training, school and public programming, summer camps, and special events. Each year, the museum serves 35,000 visitors onsite and nearly 100,000 people via its online resource materials available at www.JoCoHistory.org.
The museum is guided by two boards: the Museum Advisory Council appointed by the Johnson County Commission and the Johnson County Museum Foundation, a not-for-profit 501(c)(3) organization which raises private funds to support the museum's operation. A staff of six full-time and four part-time employees, with the help of over 50 community volunteers, oversees day-to-day museum operations.