9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Bryan | 1 | 8,539 | 8,725 | -0.36% | 1,581 | 5 | City |
| Montpelier | 2 | 3,855 | 3,942 | -0.36% | 1,341 | 3 | Village |
| Edgerton | 3 | 1,871 | 1,880 | -0.05% | 1,092 | 2 | Village |
| West Unity | 4 | 1,717 | 1,759 | -0.41% | 1,116 | 2 | Village |
| Pioneer | 5 | 1,396 | 1,429 | -0.36% | 684 | 2 | Village |
| Stryker | 6 | 1,227 | 1,259 | -0.41% | 1,371 | 1 | Village |
| Edon | 7 | 781 | 787 | -0.13% | 712 | 1 | Village |
| Blakeslee | 8 | 105 | 108 | 0% | 1,117 | 0 | Village |
| Holiday City | 9 | 49 | 51 | 0% | 19 | 3 | Village |
Bryan is the largest city in Williams County, with a population of 8,539.
Holiday City is the smallest city in Williams County, with a population of 49.
There are 9 cities in Williams County, Ohio.