Identifiers: city · CDP
| Rank | Community | Population |
|---|---|---|
| 1 | St. Louis (city), MO | 301,578 |
| 2 | O'Fallon (city), MO | 91,316 |
| 3 | St. Charles (city), MO | 70,493 |
| 4 | St. Peters (city), MO | 57,732 |
| 5 | Florissant (city), MO | 52,533 |
| 6 | Chesterfield (city), MO | 49,999 |
| 7 | Wentzville (city), MO | 44,372 |
| 8 | University City (city), MO | 35,065 |
| 9 | Ballwin (city), MO | 31,103 |
| 10 | Kirkwood (city), MO | 29,461 |
| 11 | Mehlville (CDP), MO | 28,955 |
| 12 | Maryland Heights (city), MO | 28,284 |
| 13 | Hazelwood (city), MO | 25,458 |
| 14 | Webster Groves (city), MO | 24,010 |
| 15 | Affton (CDP), MO | 20,417 |
| 16 | Old Jamestown (CDP), MO | 19,790 |
| 17 | Creve Coeur (city), MO | 18,834 |
| 18 | Ferguson (city), MO | 18,527 |
| 19 | Spanish Lake (CDP), MO | 18,413 |
| 20 | Manchester (city), MO | 18,333 |