21 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marmarth | 1 | 92 | 99 | -1.08% | 36 | 2.58 | City |
| Rainy Butte township | 2 | 37 | 38 | 0% | 1 | 35.85 | Township |
| Cash township | 3 | 35 | 36 | 0% | 1 | 35.68 | Township |
| Sand Creek township | 4 | 32 | 36 | -3.03% | 0.00 | 70.86 | Township |
| Woodberry township | 5 | 30 | 34 | -3.23% | 1 | 35.88 | Township |
| Connor township | 6 | 27 | 31 | -3.57% | 1 | 35.82 | Township |
| Moord township | 7 | 27 | 31 | -3.57% | 1 | 35.28 | Township |
| Hume township | 8 | 26 | 27 | 0% | 1 | 35.52 | Township |
| Cedar Creek township | 9 | 25 | 27 | -3.85% | 1 | 35.76 | Township |
| Mineral Springs township | 10 | 24 | 25 | 0% | 1 | 35.90 | Township |
| Amidon | 11 | 22 | 24 | 0% | 35 | 0.63 | City |
| Crawford township | 12 | 20 | 21 | 0% | 1 | 35.91 | Township |
| Peaceful Valley township | 13 | 20 | 21 | 0% | 1 | 36.87 | Township |
| Sheets township | 14 | 20 | 21 | 0% | 1 | 35.83 | Township |
| Mound township | 15 | 18 | 19 | 0% | 1 | 35.79 | Township |
| Bucklin township | 16 | 16 | 17 | 0% | 0.00 | 32.15 | Township |
| Carroll township | 17 | 15 | 14 | 0% | 0.00 | 35.99 | Township |
| White Lake township | 18 | 11 | 12 | 0% | 0.00 | 35.59 | Township |
| Hughes township | 19 | 8 | 8 | 0% | 0.00 | 35.10 | Township |
| Richland Center township | 20 | 5 | 5 | 0% | 0.00 | 35.63 | Township |
| Harper township | 21 | 0 | 0 | 0.00 | 35.67 | Township |
Marmarth is the largest city in Slope County, with a population of 92.
Harper township is the smallest city in Slope County.
There are 21 cities in Slope County, North Dakota.