20 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Sycamore township | 1 | 19,415 | 19,571 | 0.09% | 2,886 | 6.73 | Township |
| Crane township | 2 | 7,410 | 7,552 | -0.5% | 189 | 39.24 | Township |
| Upper Sandusky | 3 | 6,617 | 6,691 | -0.23% | 980 | 6.75 | City |
| Crawford township | 4 | 4,484 | 4,622 | -0.44% | 124 | 36.11 | Township |
| Carey | 5 | 3,446 | 3,558 | -0.63% | 1,596 | 2.16 | Village |
| Sycamore township | 6 | 1,417 | 1,471 | -0.49% | 59 | 24.20 | Township |
| Antrim township | 7 | 1,132 | 1,152 | 0.18% | 35 | 32.26 | Township |
| Tymochtee township | 8 | 1,057 | 1,092 | -0.47% | 29 | 36.17 | Township |
| Eden township | 9 | 983 | 1,008 | -0.2% | 32 | 30.25 | Township |
| Pitt township | 10 | 878 | 913 | -0.57% | 22 | 39.44 | Township |
| Richland township | 11 | 813 | 847 | -0.61% | 27 | 30.34 | Township |
| Sycamore | 12 | 757 | 794 | -0.92% | 1,188 | 0.64 | Village |
| Mifflin township | 13 | 748 | 770 | -0.27% | 21 | 36.48 | Township |
| Nevada | 14 | 685 | 705 | -0.58% | 668 | 1.03 | Village |
| Ridge township | 15 | 489 | 511 | -0.81% | 33 | 14.84 | Township |
| Marseilles township | 16 | 363 | 381 | -0.82% | 15 | 24.05 | Township |
| Wharton | 17 | 313 | 327 | -0.95% | 249 | 1.26 | Village |
| Harpster | 18 | 152 | 161 | -1.3% | 77 | 1.97 | Village |
| Kirby | 19 | 111 | 116 | -0.89% | 1,028 | 0.11 | Village |
| Marseilles | 20 | 92 | 97 | -1.08% | 939 | 0.10 | Village |
Sycamore township is the largest city in Wyandot County, with a population of 19,415.
Marseilles is the smallest city in Wyandot County.
There are 20 cities in Wyandot County, Ohio.