Waukesha County (/ˈwɔːkɪʃɔː/ ) 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 median income of $88,985 placed it as the only county in Wisconsin on the list of the 100 highest-income counties in the U.S. by median income as of 2020. 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.

In 2024, Waukeshaaspis, a prehistoric genus of trilobite, was named after the county.

According to the U.S. Census Bureau, the county has a total area of 581 square miles (1,500 km), of which 550 square miles (1,400 km) is land and 31 square miles (80 km) (5.3%) is water. The Fox River runs through it.

Waukesha County is located to the west of Milwaukee and its suburban development was spurred by the construction of Interstate 94 in Wisconsin.

Because of its large number of lakes, the northwestern corner of Waukesha County is referred to as "Lake Country" by local residents. It includes Pewaukee, Delafield, Hartland, Merton, Nashotah, Chenequa, Okauchee Lake, Oconomowoc, Summit, and Lac La Belle.

• Washington County – north
• Ozaukee County – northeast
• Milwaukee County – east
• Racine County – southeast
• Walworth County – southwest
• Jefferson County – west
• Dodge County – northwest

Historical population

Census	Pop.	Note	%±
1850	19,258		—
1860	26,831		39.3%
1870	28,274		5.4%
1880	28,957		2.4%
1890	33,270		14.9%
1900	35,229		5.9%
1910	37,100		5.3%
1920	42,612		14.9%
1930	52,358		22.9%
1940	62,744		19.8%
1950	85,901		36.9%
1960	158,249		84.2%
1970	231,365		46.2%
1980	280,326		21.2%
1990	304,715		8.7%
2000	360,767		18.4%
2010	389,891		8.1%
2020	406,978		4.4%
U.S. Decennial Census 1790–1960 1900–1990 1990–2000 2010–2020

As of the census of 2020, the population was 406,978. The population density was 740.3 people per square mile (285.8 people/km). There were 172,177 housing units at an average density of 313.2 units per square mile (120.9 units/km). The racial makeup of the county was 87.0% White, 3.9% Asian, 1.7% Black or African American, 0.3% Native American, 1.5% from other races, and 5.7% from two or more races. Ethnically, the population was 5.4% Hispanic or Latino of any race.

Its 2020 median income was $88,985. This ranked 97th in the nation.

At the 2010 census there were 389,891 people, 152,663 households, and 108,810 families living in the county. The population density was 672 people per square mile (259 people/km). There were 160,864 housing units at an average density of 277 units per square mile (107 units/km). The racial makeup of the county was 93.3% White, 1.3% Black or African American, 0.3% Native American, 2.7% Asian, 0.0003% Pacific Islander, 1.0% from other races, and 1.3% from two or more races. 4.1% of the population were Hispanic or Latino of any race. Of the 152,663 households 30.8% had children under the age of 18 living with them, 60.7% were married couples living together, 7.1% had a female householder with no husband present, and 28.7% were non-families. 23.8% of households were one person and 10.1% were one person aged 65 or older. The average household size was 2.52 and the average family size was 3.00.

The age distribution was 24.1% under the age of 18, 6.8% from 18 to 24, 23.6% from 25 to 44, 31.2% from 45 to 64, and 14.3% 65 or older. The median age was 42 years. For every 100 females there were 96.30 males. For every 100 females age 18 and over, there were 93.90 males.

At the 2000 census there were 360,767 people, 135,229 households, and 100,475 families living in the county. The population density was 649 people per square mile (251 people/km). There were 140,309 housing units at an average density of 252 units per square mile (97 units/km). The racial makeup of the county was 95.77% White, 0.73% Black or African American, 0.22% Native American, 1.49% Asian, 0.02% Pacific Islander, 0.87% from other races, and 0.90% from two or more races. 2.63% of the population were Hispanic or Latino of any race. 44.5% were of German, 9.2% Polish, 7.5% Italian, and 7.7% Irish ancestry according to Census 2000. 94.3% spoke English, 2.2% Spanish and 1.2% German as their first language. Of the 135,229 households 35.40% had children under the age of 18 living with them, 64.80% were married couples living together, 6.80% had a female householder with no husband present, and 25.70% were non-families. 20.90% of households were one person and 8.10% were one person aged 65 or older. The average household size was 2.63 and the average family size was 3.08.

The age distribution was 26.30% under the age of 18, 6.80% from 18 to 24, 29.80% from 25 to 44, 25.10% from 45 to 64, and 12.00% 65 or older. The median age was 38 years. For every 100 females there were 96.80 males. For every 100 females age 18 and over, there were 94.40 males.

The median household income was $62,839 and the median family income was $71,773 (these figures had risen to $71,907 and $85,116 respectively as of a 2007 estimate). Males had a median income of $49,232 versus $31,643 for females. The per capita income for the county was $29,164. About 1.7% of families and 2.7% of the population were below the poverty line, including 2.5% of those under age 18 and 4.0% of those age 65 or over.

• County Executive: Paul Farrow
• County Board Chair: Paul Decker
• County Clerk: Meg Wartman (interim)
• Treasurer: Pamela F. Reeves (R)
• Register of Deeds: James Behrend (R)
• Clerk of Circuit Court: Kathy Madden (R)
• District Attorney: Susan Opper (interim)
• Sheriff: Eric Severson (R)

There are 12 departments in Waukesha County, with most located in the Administration Center.

• Administration

The Department of Administration has five divisions that provide administrative services to the county: the finance division, the human resources division, the information technology division, the purchasing and risk management division, and the administrative services division.

• Aging and Disability Resource Center

The Aging and Disability Resource Center of Waukesha County (ADRC) provides information, assistance, counseling and supportive services regarding adults age 60 and above, adults with physical or developmental disabilities; and adults with mental health or substance abuse concerns. It also provides publicly funded long-term care to county residents.

• Airport

The Waukesha County Airport serves commercial and private aircraft and is supervised by the Airport Commission.

• Corporation Counsel
• Emergency Preparedness

The Department of Emergency Preparedness encompasses Waukesha County Communications, providing 9-1-1 dispatch services to the majority of the county, Waukesha County Emergency Management, and Waukesha County Radio Services, providing technical and maintenance support to the countywide trunked radio system (OASIS) and 9-1-1 centers.

• Bridges Library System

The Bridges Library System works in partnership with 16 public libraries in Waukesha County to cooperatively provide library services. This includes the purchase of shared electronic databases, summer library programming, and circulation services. Bridges also oversees Internet access for member libraries.

• Health and Human Services
• Medical Examiner

The Medical Examiner investigates suspicious or unexplained deaths or deaths that result from a homicide, suicide, or accident. The office also generates statistics for the county.

• Parks and Land Use

The Department of Parks and Land Use (PLU), oversees six divisions that design and maintain county parks. The division also works with state and federal agencies. The planning division administers permits for construction and landscaping activities. The land conservation division works to educate on and regulate soil and water issues. Most programs look to control water runoff and soil erosion. The recycling and solid waste division oversees recycling and disposal programs. It also performs educational outreach on topics such as composting and waste reduction. The official mascot of the recycling division is Recycle Raccoon. The environmental health division oversees animal welfare issues, food safety, and air, water and sewage, and safety issues (such as radon testing, well testing, and septic system monitoring). The land information systems division coordinates databases of information relating to land use and development.

• Public Works
• Sheriff
• University of Wisconsin Extension

The University of Wisconsin-Extension is a partnership with Waukesha County and brings the research of the UW System to families, businesses, governments, and organizations through educational outreach programs. The UW-Extension office also houses 180° Juvenile Diversion, a non-profit organization that rehabilitates first-time young offenders in Waukesha County.

• Veterans

United States presidential election results for Waukesha County, Wisconsin

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	162,768	59.02%	108,478	39.33%	4,541	1.65%
2020	159,649	59.57%	103,906	38.77%	4,441	1.66%
2016	142,543	59.99%	79,224	33.34%	15,826	6.66%
2012	162,798	66.76%	78,779	32.31%	2,279	0.93%
2008	145,152	62.32%	85,339	36.64%	2,406	1.03%
2004	154,926	67.25%	73,626	31.96%	1,811	0.79%
2000	133,105	65.33%	64,319	31.57%	6,310	3.10%
1996	91,729	55.43%	57,354	34.66%	16,389	9.90%
1992	91,461	51.04%	50,270	28.06%	37,451	20.90%
1988	90,467	60.76%	57,598	38.68%	828	0.56%
1984	92,426	65.71%	47,313	33.64%	921	0.65%
1980	81,059	58.25%	46,612	33.50%	11,477	8.25%
1976	70,418	58.22%	47,487	39.26%	3,048	2.52%
1972	59,399	60.85%	34,573	35.42%	3,650	3.74%
1968	47,557	54.98%	31,947	36.93%	7,000	8.09%
1964	35,502	47.07%	39,796	52.76%	131	0.17%
1960	39,380	57.56%	28,963	42.33%	76	0.11%
1956	35,212	68.93%	15,496	30.33%	376	0.74%
1952	30,238	65.58%	15,756	34.17%	117	0.25%
1948	17,324	54.22%	13,952	43.67%	674	2.11%
1944	17,995	57.44%	13,038	41.62%	293	0.94%
1940	16,726	55.86%	12,859	42.94%	358	1.20%
1936	8,921	35.41%	14,982	59.47%	1,291	5.12%
1932	8,538	37.76%	13,487	59.65%	584	2.58%
1928	12,218	60.15%	7,846	38.63%	247	1.22%
1924	7,026	45.45%	1,965	12.71%	6,468	41.84%
1920	8,665	71.63%	2,759	22.81%	673	5.56%
1916	3,768	45.21%	4,192	50.29%	375	4.50%
1912	2,714	36.86%	3,594	48.81%	1,055	14.33%
1908	4,758	55.91%	3,206	37.67%	546	6.42%
1904	5,247	62.63%	2,693	32.14%	438	5.23%
1900	5,127	60.91%	3,016	35.83%	275	3.27%
1896	5,411	60.93%	3,192	35.95%	277	3.12%
1892	3,600	47.54%	3,635	48.01%	337	4.45%

Waukesha County is the largest Republican-leaning county in Wisconsin and has been one of the most Republican suburban counties in the nation for many years. It is one of the WOW counties, which share similar traits in suburban Milwaukee.

It has not supported a Democrat for president since 1964, and has only supported a Democrat four other times since 1892. While other non-Southern suburban counties have moved towards Democrats since the 1990s, Waukesha and the other WOW counties have continued to vote solidly Republican. Underlining this, Lyndon Johnson's narrow win in 1964 is the last time that a Democratic presidential candidate has even garnered 40 percent of the county's vote, though Jimmy Carter, Michael Dukakis, Joe Biden, and Kamala Harris came close. In 2008, John McCain carried the county by a 25.7% margin over Barack Obama, when Obama won Wisconsin by 13.9% over McCain. In 2024, Kamala Harris became the first Democrat since 1976 to lose the county by less than 20 percentage points.

The county's Republican bent is not limited to national politics. The county rejects Democrats at the state and local level as well. It last supported a Democrat for governor in 1974, one of only five times it did so in the 20th century even though it was known to support Progressive candidates in the 1930s and 1940s. It is split between 10 state assembly districts, all but one of which are held by Republicans, and six state senate districts, all held by Republicans. In much of the county, there are no elected Democrats above the municipal level.

The initial unofficial statewide tally in the 2011 Wisconsin Supreme Court election had Democratic challenger JoAnne Kloppenburg defeating incumbent justice David Prosser by a 204-vote margin. On the Thursday after the election, Waukesha County Clerk Kathy Nickolaus reported, among other smaller errors, a failure to report votes in the Waukesha city of Brookfield. The newly reported votes gave Prosser the lead, and he retained his seat. Media reports stemming from this incident referred to the county as "crucial Waukesha County," and the phrase has continued to be widely used in U.S. political media as an in-joke, despite the county being a Republican stronghold.

• North Lake
• Okauchee Lake

• Calhoun
• Dodges Corners
• DeNoon
• Duplainville
• Muskego Settlement
• New Upsala

Note – for zoning purposes, a single acre of Waukesha County was annexed by the city of Milwaukee in 2003 to accommodate the Ambrosia Chocolate Factory.

Waukesha County Climate chart (explanation) J F M A M J J A S O N D     102     −6 −14     96     −4 −12     69     5 −5     160     18 3     102     23 9     148     25 14     95     27 17     105     26 17     70     22 13     95     15 5     66     8 −1     79     −2 −11 █ Average max. and min. temperatures in °C █ Precipitation totals in mm Source: Imperial conversion J F M A M J J A S O N D     4     21 7     3.8     25 10     2.7     41 23     6.3     64 37     4     73 48     5.8     77 57     3.7     81 63     4.1     79 63     2.8     72 55     3.7     59 41     2.6     46 30     3.1     28 12 █ Average max. and min. temperatures in °F █ Precipitation totals in inches

School districts include:

K-12:

Secondary:

• Arrowhead Union High School District
• Waterford Union High School District

Elementary:

• Canadian National
• Canadian Pacific
• Union Pacific
• Wisconsin and Southern Railroad

• Waukesha Metro Transit

• National Register of Historic Places listings in Waukesha County, Wisconsin
• Waukesha County gangsters
• Waukesha County Park System
• Waukesha, Wisconsin
• Waukesha (village), Wisconsin

• Haight, Theron W. (ed.) Memoirs of Waukesha County. Madison: Western Historical Association, 1907.
• The History of Waukesha County, Wisconsin. Chicago: Western Historical Company, 1880.
• Portrait and Biographical Record of Waukesha County, Wisconsin. Chicago: Excelsior Publishing Co. 1894.

• Official website

43°01′N 88°19′W / 43.02°N 88.31°W / 43.02; -88.31