Here are the 10 Most Populated Counties in Missouri from the 2020 Census.
- Saint Louis 1,000,438
- Jackson 674,158
- Saint Charles 360,485
- Saint Louis City 319,294
- Greene 275,174
- Clay 221,939
- Jefferson 218,733
- Boone 162,642
- Jasper 117,404
- Franklin 101,492