Shelby County is a county located in the northeastern portion of the U.S. state of Missouri. As of the 2020 census, the population was 6,103. Its county seat is Shelbyville. The county was established on January 2, 1835, and named for Governor Isaac Shelby of Kentucky.

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.