22 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Carrington | 1 | 1,963 | 2,077 | -1.16% | 828 | 2.37 | City |
| Carrington township | 2 | 212 | 224 | -2.3% | 6 | 33.81 | Township |
| Glenfield | 3 | 95 | 94 | 0% | 693 | 0.14 | City |
| Birtsell township | 4 | 90 | 94 | -2.17% | 3 | 35.75 | Township |
| Rose Hill township | 5 | 76 | 77 | -1.3% | 2 | 35.10 | Township |
| Nordmore township | 6 | 71 | 75 | -2.74% | 2 | 35.54 | Township |
| Wyard township | 7 | 67 | 71 | -2.9% | 2 | 34.57 | Township |
| McHenry | 8 | 63 | 63 | 0% | 256 | 0.25 | City |
| Estabrook township | 9 | 60 | 64 | -3.23% | 2 | 35.88 | Township |
| Bordulac township | 10 | 54 | 59 | -3.57% | 2 | 34.03 | Township |
| Larrabee township | 11 | 54 | 58 | -3.57% | 2 | 34.96 | Township |
| Grace City | 12 | 53 | 53 | 0% | 216 | 0.24 | City |
| Glenfield township | 13 | 49 | 51 | -2% | 1 | 35.71 | Township |
| Florance township | 14 | 47 | 47 | 0% | 1 | 34.73 | Township |
| Longview township | 15 | 47 | 51 | -2.08% | 1 | 35.36 | Township |
| Melville township | 16 | 45 | 49 | -2.17% | 1 | 34.33 | Township |
| Haven township | 17 | 35 | 36 | 0% | 1 | 35.29 | Township |
| Bucephalia township | 18 | 34 | 35 | 0% | 1 | 35.43 | Township |
| McHenry township | 19 | 33 | 35 | -2.94% | 1 | 33.63 | Township |
| Rolling Prairie township | 20 | 31 | 34 | -3.13% | 1 | 35.69 | Township |
| McKinnon township | 21 | 22 | 25 | -4.35% | 1 | 35.67 | Township |
| Eastman township | 22 | 12 | 15 | -7.69% | 0.00 | 35.60 | Township |
Carrington is the largest city in Foster County, with a population of 1,963.
Eastman township is the smallest city in Foster County.
There are 22 cities in Foster County, North Dakota.