5 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Lebanon | 1 | 6,624 | 6,291 | 1.01% | 969 | 7 | City |
| Loretto | 2 | 708 | 718 | -0.28% | 222 | 3 | City |
| Bradfordsville | 3 | 274 | 267 | 0.37% | 1,015 | 0 | City |
| Raywick | 4 | 154 | 154 | 0% | 172 | 1 | City |
| St. Mary | 5 | 140 | 139 | 0% | 180 | 1 | City |
Lebanon is the largest city in Marion County, with a population of 6,624.
St. Mary is the smallest city in Marion County, with a population of 140.
There are 5 cities in Marion County, Kentucky.