| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marion | 1 | 28,201 | 28,246 | -0.12% | 1,796 | 16 | City |
| Gas City | 2 | 6,061 | 6,140 | -0.33% | 1,206 | 5 | City |
| Upland | 3 | 3,835 | 3,822 | 0% | 1,222 | 3 | Town |
| Fairmount | 4 | 2,666 | 2,675 | -0.15% | 1,681 | 2 | Town |
| Jonesboro | 5 | 1,508 | 1,508 | -0.13% | 1,689 | 1 | City |
| Sweetser | 6 | 1,068 | 1,067 | -0.09% | 1,060 | 1 | Town |
| Swayzee | 7 | 901 | 913 | -0.33% | 1,921 | 0 | Town |
| Van Buren | 8 | 774 | 777 | -0.13% | 1,328 | 1 | Town |
| Matthews | 9 | 484 | 480 | 0% | 1,375 | 0 | Town |
| Fowlerton | 10 | 271 | 268 | 0% | 1,383 | 0 | Town |
Marion is the largest city in Grant County, with a population of 28,201.
Fowlerton is the smallest city in Grant County, with a population of 271.
There are 10 cities in Grant County, Indiana.