Mequon is the most populous city in Ozaukee County, Wisconsin, United States. The population was 25,142 at the 2020 census. Located on Lake Michigan's western shore with significant commercial developments along Interstate 43, the community is a suburb in the Milwaukee metropolitan area. Despite being the third-largest city in Wisconsin by land area, approximately half of Mequon's land is undeveloped, and agriculture plays a significant role in the local economy.