Map - Waukesha County, Wisconsin (Waukesha County)

Waukesha County is a county in the U.S. state of Wisconsin. As of the 2020 United States Census, the population was 406,978, making it the third-most populous county in Wisconsin. Its county seat and largest city is Waukesha.

Waukesha County is included in the Milwaukee–Waukesha–West Allis, WI Metropolitan Statistical Area.

Known as forested and prairie land, the region was first home to Indigenous tribes like Menomonie, Ojibwe (Chippewa), Potawatomi, and Ho-Chunk (Winnebago), who practiced agriculture and trade. In 1836, Native American tribes formally lost title to the land when treaties were disregarded and were forcibly removed by the Federal Army. Prior to the 1830s, the area was unoccupied by settlers due to its inland location and the fact that the Fox River was not a water highway. The New England settlers only came to the area to set up fur trading posts between their new encampments and established cities like Milwaukee. Morris D. Cutler and Alonso Cutler, seeking claims for homesteads, were the first permanent white colonial settlers.

The part of Wisconsin that Waukesha County occupies was a part of Michigan Territory when Milwaukee County was organized in September 1834. On July 4, 1836, the Wisconsin Territory was formed, which included land that is now in the state of Minnesota. In January 1846, part of Milwaukee County was split off into Waukesha County. Curtis Reed was the first county chairman. When a vote decided the county seat, Waukesha defeated Pewaukee by two votes. The name is derived from the Potawatomi word for 'fox' because the streams in the lower part of the county drain into the Fox River.

Waukesha was a New England settlement, and Waukesha's founders were settlers from New England, particularly Connecticut, rural Massachusetts, Vermont, New Hampshire and Maine, as well as from upstate New York who were born to parents who had migrated there from New England shortly after the American Revolution. These people were "Yankees" descended from the English Puritans who settled New England in the 1600s. They were part of a wave of New England farmers who headed west into what was the wilds of the Northwest Territory during the early 1800s. Most arrived as a result of the completion of the Erie Canal as well as the end of the Black Hawk War.

The New Englanders built farms, roads, government buildings and established post routes. They brought many of their Yankee New England values, such as a passion for education that led to the establishment of many schools as well as staunch support for abolitionism. They were mostly members of the Congregationalist Church, though some were Episcopalian. Due to the second Great Awakening some converted to Methodism, and others became Baptists before moving to what is now Waukesha County. Waukesha, like much of Wisconsin, would be culturally very continuous with early New England culture for most of its early history, before the state received a substantial influx of German immigrants in the latter half of the 19th century.