Missouri's second congressional district is in the eastern portion of the state, primarily consisting of the suburbs south and west of St. Louis, including Arnold, Town and Country, Wildwood, Chesterfield, and Oakville. The district includes all of Franklin County and portions of St. Louis, St. Charles, and Warren counties. Following redistricting in 2010, the St. Louis Post-Dispatch reported that the district now included more Democratic-leaning voters than it had its 2001–2010 boundaries, but still leaned Republican as a whole. The latest U.S. Census Electorate Profile for the 2nd congressional district estimates there are 581,131 citizens of voting age living in 293,984 households. A primarily suburban district, MO-02 is the wealthiest of Missouri's congressional districts.

Franklin County is located in the U.S. state of Missouri. At the 2020 census, the population was 104,682. Its county seat is Union. The county was organized in 1818 and is named after Founding Father Benjamin Franklin.