| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kirksville | 1 | 17,934 | 17,529 | 0.4% | 1,247 | 14 | City |
| Greentop | 2 | 392 | 379 | 0.26% | 480 | 1 | City |
| Novinger | 3 | 386 | 383 | 0% | 490 | 1 | City |
| Brashear | 4 | 240 | 239 | 0% | 686 | 0 | City |
| Millard | 5 | 78 | 78 | 0% | 650 | 0 | Village |
| Gibbs | 6 | 71 | 71 | 0% | 286 | 0 | Village |
| South Gifford | 7 | 23 | 23 | 0% | 112 | 0 | Village |
Kirksville is the largest city in Adair County, with a population of 17,934.
South Gifford is the smallest city in Adair County, with a population of 23.
There are 7 cities in Adair County, Missouri.