Founded in 1818, Franklin County is one of 114 counties in the state of Missouri. Historically, Franklin County was formed from St. Louis County. The city of Union is the county seat. With FIPS code of 71, Franklin County has a population of 105,231 and area of 922 square miles (2,388 km2).
List of all cities in Franklin County, MO alphabetically
| City/Town | Postal Code | Area Code |
| Beaufort, MO | 63013 | 573 |
| Berger, MO | 63014 | 573 |
| Campbellton, MO | 63068 | 573 |
| Campbellton, MO | 63090 | 636 |
| Catawissa, MO | 63015 | 636 |
| Clover Bottom, MO | 63090 | 636 |
| Detmold, MO | 63068 | 573 |
| Dissen, MO | 63068 | 573 |
| Etlah, MO | 63014 | 573 |
| Gerald, MO | 63037 | 573 |
| Gray Summit, MO | 63039 | 636 |
| Grubville, MO | 63041 | 636 |
| Japan, MO | 63080 | 573 |
| Labadie, MO | 63055 | 636 |
| Leslie, MO | 63056 | 573 |
| Lonedell, MO | 63060 | 636 |
| Luebbering, MO | 63061 | 636 |
| Lyon, MO | 63068 | 573 |
| Moselle, MO | 63084 | 636 |
| New Haven, MO | 63068 | 573 |
| Pacific, MO | 63055 | 636 |
| Pacific, MO | 63069 | 636 |
| Pea Ridge, MO | 63080 | 573 |
| Robertsville, MO | 63072 | 636 |
| Saint Albans, MO | 63073 | 636 |
| Saint Clair, MO | 63077 | 636 |
| Spring Bluff, MO | 63080 | 573 |
| Stanton, MO | 63079 | 573 |
| Stony Hill, MO | 63068 | 573 |
| Strain, MO | 63080 | 573 |
| Sullivan, MO | 63080 | 573 |
| Union, MO | 63084 | 636 |
| Villa Ridge, MO | 63089 | 636 |
| Washington, MO | 63090 | 636 |
| Wildwood, MO | 63069 | 636 |