Port Washington is a city in Ozaukee County, Wisconsin, United States, and its county seat. Located on Lake Michigan's western shore east of Interstate 43, the community is a suburb in the Milwaukee metropolitan area 27 miles north of Milwaukee. The city's artificial harbor at the mouth of Sauk Creek was dredged in the 1870s and was a commercial port until the early 2000s. The population was 12,353 at the 2020 census.