Barton County is a county located in the southwestern part of the U.S. state of Missouri. As of the 2020 census, the population was 11,637. Its county seat is Lamar. The county was organized in 1855 and named after U.S. Senator David Barton from Missouri.

The Missouri House of Representatives is the lower chamber of the Missouri General Assembly. It has 163 members, representing districts with an average size of 37,000 residents. House members are elected for two-year terms during general elections held in even-numbered years.