Missouri's 3rd Senatorial District is one of 34 districts in the Missouri Senate. The district has been represented by Republican Mike Henderson since 2025.
The district includes southwestern portions of the St. Louis metropolitan area and includes Crawford, St. Francois, Ste. Genevieve, Washington, and southern Jefferson counties. Major municipalities in the district include Bloomsdale, Bonne Terre, Cuba, De Soto, Farmington, and Park Hills. The district also includes a portion of Mark Twain National Forest.
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