Missouri became a state of the United States of America on August 10, 1821.
The U.S. state of Missouri is divided into 114 counties and one independent city. Cape Girardeau, New Madrid, Saint Charles, Saint Louis, and Sainte Genevieve counties were the first counties created on October 1, 1812, and the last county to be formed was Worth County on February 8, 1861.
Missouri’s counties evolved through various territorial designations—starting as the District of Louisiana in 1804 and becoming the Missouri Territory in 1812 with its original five foundational counties—before statehood in 1821.
Former counties and history
Dodge County: Formed February 27, 1849, from Putnam County and named for U.S. Senator Augustus C. Dodge; dissolved February 23, 1853, after a Supreme Court boundary ruling reduced its tax base, with land returned to Putnam County.
Lillard County: Created January 1, 1821, from Cooper County, named after pioneer James Lillard; renamed Lafayette County on February 16, 1825, after Lillard moved to Tennessee.
Niangua County: Established January 29, 1841, from Polk County, named for the Niangua River; renamed Dallas County on December 16, 1844, due to difficulties pronouncing and spelling the original name.
Rives County: Formed December 13, 1834, named for Virginia Senator William C. Rives; renamed Henry County on February 15, 1841, after Rives broke with the Democratic Party.
Seneca County: Created February 24, 1847, from Newton County, named for the local Seneca people; reorganized and renamed McDonald County on November 3, 1849.
Van Buren County: Established March 3, 1835, from Jackson County, named for Vice President Martin Van Buren; renamed Cass County on February 19, 1849, following Van Buren’s Free Soil presidential run.