| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mequon | 1 | 25,143 | 25,140 | 0.09% | 543 | 46 | City |
| Grafton | 2 | 13,538 | 12,072 | 1.11% | 2,585 | 5 | Village |
| Cedarburg | 3 | 13,104 | 12,198 | 1.46% | 2,663 | 5 | City |
| Port Washington | 4 | 12,720 | 12,435 | 0.49% | 2,136 | 6 | City |
| Saukville | 5 | 4,562 | 4,252 | 0.18% | 1,289 | 4 | Village |
| Thiensville | 6 | 3,267 | 3,286 | 0% | 3,147 | 1 | Village |
| Belgium | 7 | 2,558 | 2,437 | 0.71% | 1,190 | 2 | Village |
| Fredonia | 8 | 2,251 | 2,272 | -0.04% | 1,007 | 2 | Village |
Mequon is the largest city in Ozaukee County, with a population of 25,143.
Fredonia is the smallest city in Ozaukee County, with a population of 2,251.
There are 8 cities in Ozaukee County, Wisconsin.