St. Croix County is a county in the U.S. state of Wisconsin. As of the 2020 census, the population was 93,536. Its county seat is Hudson. The county was created in 1840 (then in the Wisconsin Territory) and organized in 1849. St. Croix County is part of the Minneapolis-St. Paul-Bloomington, MN-WI Metropolitan Statistical Area. Between 2000 and 2010, it was the fastest-growing county in Wisconsin.

St. Croix County was created on August 3, 1840 by the legislature of the Wisconsin Territory. It was named after the river on its western border. Sources vary on the origin of the name; the St. Croix River may have been named after Monsieur St. Croix, an explorer who drowned at the mouth of the river late in the seventeenth century. Another account credits Father Hennepin with giving this region the French name St Croix (Holy Cross) because of the burial markers located at the mouth of the river.

La Pointe County (now extinct, see Bayfield County) was created from the northern portions of Wisconsin Territory's St. Croix County on February 19, 1845. When Wisconsin was admitted into the union as a state on May 29, 1848, the territorial St. Croix County was further divided, with the territory from the Mississippi River to the current border of Minnesota continuing as de facto Wisconsin Territory until on March 3, 1849, it and unorganized federal territory lying north of Iowa were used in the creation of the Minnesota Territory. Itasca, Washington, Ramsey and Benton Counties were created by the Minnesota Territory on October 27, 1849 from the de facto Wisconsin Territory that had been separated from the Wisconsin Territory's La Pointe County.

The part of St. Croix County allocated to Wisconsin became the parental county to Pierce and Polk Counties, and formed significant portions of Dunn, Barron, Washburn and Burnett Counties.

On June 12, 1899, a deadly F5 tornado struck New Richmond. The tornado's damage path was 400 yards (370 m) wide and 46 miles (74 km) long. The tornado formed on the banks of the St. Croix River, south of Hudson. Moving to the northeast across St. Croix County, the tornado passed through the villages of Burkhardt and Boardman before striking New Richmond head on leveling the entire business district and half the town's residences. The storm continued on towards the northeast, narrowly missing the town of Deer Park before crossing into Polk County, where it again narrowly missed the towns of Clear Lake, Richardson and Clayton. Once the tornado passed into Barron County, it struck the village of Arland (No reported fatalities or serious injuries) before breaking up southwest of Barron. The tornado killed 117 people (Four at Boardman, two in Polk County and the rest at New Richmond), including at least 20 people who died from their injuries in the days after the storm. Largely in thanks to state aid and donations, most of the town was rebuilt by the following winter. Today, the tornado stands as the deadliest ever recorded in Wisconsin and the 9th deadliest tornado in U.S. history.

According to the U.S. Census Bureau, the county has a total area of 736 square miles (1,910 km), of which 722 square miles (1,870 km) is land and 13 square miles (34 km) (1.8%) is water.

Interstate 94 US Highway 12 US Highway 63

Wisconsin Highway 29 Wisconsin Highway 35 Wisconsin Highway 46

Wisconsin Highway 64 Wisconsin Highway 65 Wisconsin Highway 128

Wisconsin Highway 170 List of county roads

• Canadian National
• Union Pacific

New Richmond Regional Airport (KRNH) serves the county and surrounding communities.

• Saint Croix National Scenic Riverway (part)

• Polk County - north
• Barron County - northeast
• Dunn County - east
• Pierce County - south
• Washington County, Minnesota - west

Historical population

Census	Pop.	Note	%±
1840	809		—
1850	624		−22.9%
1860	5,392		764.1%
1870	11,035		104.7%
1880	18,956		71.8%
1890	23,139		22.1%
1900	26,830		16.0%
1910	25,910		−3.4%
1920	26,106		0.8%
1930	25,455		−2.5%
1940	24,842		−2.4%
1950	25,905		4.3%
1960	29,164		12.6%
1970	34,354		17.8%
1980	43,262		25.9%
1990	50,251		16.2%
2000	63,155		25.7%
2010	84,345		33.6%
2020	93,536		10.9%
U.S. Decennial Census 1790–1960 1900–1990 1990–2000 2010–2020

As of the census of 2020, the population was 93,536. The population density was 129.5 people per square mile (50.0 people/km). There were 37,369 housing units at an average density of 51.7 units per square mile (20.0 units/km). The racial makeup of the county was 92.2% White, 1.1% Asian, 0.7% Black or African American, 0.3% Native American, 1.1% from other races, and 4.5% from two or more races. Ethnically, the population was 2.9% Hispanic or Latino of any race.

As of the census of 2000, there were 63,155 people, 23,410 households, and 16,948 families residing in the county. The population density was 88 people per square mile (34 people/km). There were 24,265 housing units at an average density of 34 units per square mile (13 units/km). The racial makeup of the county was 97.85% White, 0.28% Black or African American, 0.25% Native American, 0.62% Asian, 0.02% Pacific Islander, 0.22% from other races, and 0.76% from two or more races. 0.76% of the population were Hispanic or Latino of any race. 34.4% were of German, 19.3% Norwegian, 8.2% Irish and 5.4% Swedish ancestry.

There were 23,410 households, out of which 38.00% had children under the age of 18 living with them, 61.60% were married couples living together, and 27.60% were non-families. 21.20% of all households were made up of individuals, and 7.30% had someone living alone who was 65 years of age or older. The average household size was 2.66 and the average family size was 3.12.

In the county, the population was spread out, with 27.90% under the age of 18, 8.20% from 18 to 24, 32.20% from 25 to 44, 21.90% from 45 to 64, and 9.90% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 100.20 males. For every 100 females age 18 and over, there were 98.50 males.

In 2017, there were 988 births, giving a general fertility rate of 59.0 births per 1000 women aged 15–44, the 25th lowest rate out of all 72 Wisconsin counties.

• Glenwood City
• Hudson (county seat)
• New Richmond
• River Falls (mostly in Pierce County)

• Emerald
• Houlton

United States presidential election results for St. Croix County, Wisconsin

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2020	32,199	56.78%	23,190	40.89%	1,318	2.32%
2016	26,222	55.19%	17,482	36.80%	3,804	8.01%
2012	25,503	55.17%	19,910	43.07%	812	1.76%
2008	22,837	50.95%	21,177	47.25%	807	1.80%
2004	22,679	54.21%	18,784	44.90%	372	0.89%
2000	15,240	50.88%	13,077	43.66%	1,637	5.47%
1996	8,253	35.55%	11,384	49.04%	3,576	15.41%
1992	8,114	31.60%	10,281	40.04%	7,281	28.36%
1988	9,960	46.25%	11,392	52.90%	181	0.84%
1984	11,367	52.54%	10,127	46.81%	141	0.65%
1980	9,265	42.56%	10,203	46.87%	2,299	10.56%
1976	7,685	41.16%	10,601	56.77%	386	2.07%
1972	8,553	52.50%	7,488	45.96%	250	1.53%
1968	6,595	46.61%	6,807	48.11%	746	5.27%
1964	4,565	33.92%	8,864	65.86%	29	0.22%
1960	7,113	52.77%	6,341	47.05%	24	0.18%
1956	6,956	55.72%	5,499	44.05%	29	0.23%
1952	7,607	59.78%	5,094	40.03%	25	0.20%
1948	4,326	40.43%	6,173	57.69%	202	1.89%
1944	5,660	53.01%	4,930	46.17%	88	0.82%
1940	6,857	57.74%	4,898	41.24%	121	1.02%
1936	4,316	38.47%	4,679	41.71%	2,223	19.82%
1932	4,059	37.94%	6,374	59.58%	265	2.48%
1928	6,855	62.17%	4,083	37.03%	88	0.80%
1924	3,600	39.68%	718	7.91%	4,755	52.41%
1920	5,601	73.34%	1,638	21.45%	398	5.21%
1916	2,731	51.09%	2,352	44.00%	262	4.90%
1912	1,728	37.18%	1,806	38.86%	1,114	23.97%
1908	3,228	62.29%	1,773	34.21%	181	3.49%
1904	3,898	68.33%	1,569	27.50%	238	4.17%
1900	3,368	58.98%	2,076	36.36%	266	4.66%
1896	3,462	56.38%	2,475	40.31%	203	3.31%
1892	2,467	47.04%	2,220	42.33%	557	10.62%

• National Register of Historic Places listings in St. Croix County, Wisconsin

• Johnson, Helen Sophia. Early History of St. Croix County, Wisconsin. Madison: University of Wisconsin, 1921.

• St. Croix County government website
• St. Croix County map at the Wisconsin Department of Transportation

45°02′N 92°27′W / 45.04°N 92.45°W / 45.04; -92.45