Jefferson County is located in the eastern portion of the state of Missouri. It is a part of the St. Louis Metropolitan Area. As of the 2010 census, the population was 218,733, making it the sixth-most populous county in Missouri. Its county seat is Hillsboro. The county was organized in 1818 and named in honor of former president Thomas Jefferson.
The Jefferson County Commission is committed to the continued economic vitality of county while maintaining the highest quality of life for residents. Jefferson County’s goal is to provide continuous improvement of education and services for all citizens. Jefferson County Parks are open for everyone to use.