8 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kirksville | 1 | 17,461 | 17,516 | -0.06% | 1,214 | 14 | City |
| Greentop | 2 | 387 | 384 | 0.26% | 474 | 1 | City |
| Novinger | 3 | 371 | 383 | -0.54% | 471 | 1 | City |
| Brashear | 4 | 236 | 241 | -0.42% | 674 | 0 | City |
| Connelsville | 5 | 110 | 111 | 6.8% | 332 | 0 | CDP |
| Millard | 6 | 74 | 76 | 0% | 617 | 0 | Village |
| Gibbs | 7 | 68 | 70 | 0% | 274 | 0 | Village |
| South Gifford | 8 | 23 | 23 | 0% | 112 | 0 | Village |
Kirksville is the largest city in Adair County, with a population of 17,461.
South Gifford is the smallest city in Adair County, with a population of 23.
There are 8 cities in Adair County, Missouri.