9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| South Bend | 1 | 103,894 | 103,350 | 0.09% | 2,480 | 42 | City |
| Mishawaka | 2 | 51,006 | 51,047 | -0.01% | 2,800 | 18 | City |
| Osceola | 3 | 2,608 | 2,584 | 0.15% | 1,932 | 1 | Town |
| Walkerton | 4 | 2,100 | 2,093 | 0.05% | 1,105 | 2 | Town |
| New Carlisle | 5 | 1,924 | 1,891 | 0.31% | 948 | 2 | Town |
| North Liberty | 6 | 1,635 | 1,626 | 0.12% | 1,590 | 1 | Town |
| Lakeville | 7 | 880 | 874 | 0.11% | 1,406 | 1 | Town |
| Roseland | 8 | 854 | 851 | 0.12% | 2,265 | 0 | Town |
| Indian Village | 9 | 114 | 116 | 0% | 1,267 | 0 | Town |
South Bend is the largest city in St. Joseph County, with a population of 103,894.
Indian Village is the smallest city in St. Joseph County, with a population of 114.
There are 9 cities in St. Joseph County, Indiana.