9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Mequon | 1 | 25,681 | 25,201 | 0.38% | 555 | 46.28 | City |
| Port Washington | 2 | 13,007 | 12,396 | 0.95% | 2,185 | 5.95 | City |
| Grafton | 3 | 12,957 | 12,084 | 1.37% | 2,474 | 5.24 | Village |
| Cedarburg | 4 | 12,765 | 12,169 | 0.94% | 2,594 | 4.92 | City |
| Saukville | 5 | 4,262 | 4,257 | 0.02% | 1,204 | 3.54 | Village |
| Thiensville | 6 | 3,284 | 3,284 | 0% | 3,164 | 1.04 | Village |
| Belgium | 7 | 2,539 | 2,428 | 0.87% | 1,181 | 2.15 | Village |
| Fredonia | 8 | 2,290 | 2,275 | 0.13% | 1,024 | 2.24 | Village |
| Waubeka | 9 | 496 | 624 | -1.98% | 202 | 2.45 | CDP |
Mequon is the largest city in Ozaukee County, with a population of 25,681.
Waubeka is the smallest city in Ozaukee County.
There are 9 cities in Ozaukee County, Wisconsin.