4 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Carrington | 1 | 1,988 | 2,080 | -0.75% | 838 | 2 | City |
| Glenfield | 2 | 95 | 95 | 0% | 693 | 0 | City |
| McHenry | 3 | 63 | 63 | 0% | 256 | 0 | City |
| Grace City | 4 | 54 | 54 | 0% | 220 | 0 | City |
Carrington is the largest city in Foster County, with a population of 1,988.
Grace City is the smallest city in Foster County, with a population of 54.
There are 4 cities in Foster County, North Dakota.