| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Pittsfield | 1 | 4,014 | 4,169 | -0.67% | 839 | 5 | City |
| Barry | 2 | 1,237 | 1,293 | -0.8% | 864 | 1 | City |
| Griggsville | 3 | 1,037 | 1,091 | -0.96% | 938 | 1 | City |
| Pleasant Hill | 4 | 890 | 914 | -0.56% | 1,163 | 1 | Village |
| Hull | 5 | 372 | 392 | -1.06% | 204 | 2 | Village |
| New Canton | 6 | 322 | 333 | -0.92% | 365 | 1 | Town |
| Perry | 7 | 300 | 312 | -0.66% | 777 | 0 | Village |
| Nebo | 8 | 268 | 276 | -0.74% | 618 | 0 | Village |
| Milton | 9 | 205 | 209 | -0.49% | 531 | 0 | Village |
| Kinderhook | 10 | 187 | 191 | -0.53% | 231 | 1 | Village |
| Baylis | 11 | 164 | 169 | -0.61% | 348 | 0 | Village |
| New Salem | 12 | 115 | 120 | -0.86% | 110 | 1 | Village |
| Pearl | 13 | 107 | 110 | -0.93% | 71 | 2 | Village |
| Detroit | 14 | 74 | 74 | 0% | 295 | 0 | Village |
| Florence | 15 | 16 | 18 | -5.88% | 58 | 0 | Village |
| Valley City | 16 | 13 | 12 | 0% | 48 | 0 | Village |
Pittsfield is the largest city in Pike County, with a population of 4,014.
Valley City is the smallest city in Pike County, with a population of 13.
There are 16 cities in Pike County, Illinois.