17 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mequon | 1 | 25,377 | 25,147 | 0.19% | 548 | 46 | City |
| Mequon | 2 | 25,377 | 25,136 | 0.19% | 548 | 46 | City |
| Cedarburg | 3 | 13,213 | 12,132 | 1.55% | 2,685 | 5 | City |
| Cedarburg | 4 | 13,213 | 12,201 | 1.55% | 2,685 | 5 | City |
| Grafton | 5 | 12,904 | 12,089 | 1.28% | 2,464 | 5 | Village |
| Grafton | 6 | 12,904 | 12,087 | 1.28% | 2,464 | 5 | Village |
| Port Washington | 7 | 12,828 | 12,352 | 0.61% | 2,155 | 6 | City |
| Port Washington | 8 | 12,828 | 12,435 | 0.61% | 2,155 | 6 | City |
| Saukville | 9 | 4,318 | 4,259 | 0.3% | 1,220 | 4 | Village |
| Saukville | 10 | 4,318 | 4,252 | 0.3% | 1,220 | 4 | Village |
| Thiensville | 11 | 3,302 | 3,290 | 0.09% | 3,181 | 1 | Village |
| Thiensville | 12 | 3,302 | 3,285 | 0.09% | 3,181 | 1 | Village |
| Belgium | 13 | 2,535 | 2,426 | 0.8% | 1,180 | 2 | Village |
| Belgium | 14 | 2,535 | 2,432 | 0.8% | 1,180 | 2 | Village |
| Fredonia | 15 | 2,283 | 2,277 | 0.09% | 1,021 | 2 | Village |
| Fredonia | 16 | 2,283 | 2,273 | 0.09% | 1,021 | 2 | Village |
| Waubeka | 17 | 496 | 624 | -1.98% | 202 | 2 | CDP |
Mequon is the largest city in Ozaukee County, with a population of 25,377.
Waubeka is the smallest city in Ozaukee County, with a population of 496.
There are 17 cities in Ozaukee County, Wisconsin.