Isanti County (/aɪˈsæntiː/ eye-SAN-tee) is a county in the east-central part of the U.S. state of Minnesota. As of the 2020 census, the population was 41,135. Its county seat is Cambridge.

The county was formed on February 13, 1857. Its name came from the Izaty Indians, the ancient name for the Santee Indians, members of the Dakota alliance. Isanti is derived from the Dakota word for "knife" and refers to the Santee tribe.

Isanti County is included in the Minneapolis-St. Paul-Bloomington Metropolitan Statistical Area.

The Rum River flows south through the county's central part. The county's terrain is hilly and etched with drainages and gullies, and dotted with lakes and ponds. The terrain generally slopes to the south and east; its highest point is near its northwest corner, at 1,020 ft (310 m) ASL. The county has an area of 452 square miles (1,170 km), of which 436 square miles (1,130 km) is land and 16 square miles (41 km) (3.5%) is water.

Source:

Historical population

Census	Pop.	Note	%±
1860	284		—
1870	2,035		616.5%
1880	5,063		148.8%
1890	7,607		50.2%
1900	11,675		53.5%
1910	12,615		8.1%
1920	13,278		5.3%
1930	12,081		−9.0%
1940	12,950		7.2%
1950	12,123		−6.4%
1960	13,530		11.6%
1970	16,560		22.4%
1980	23,600		42.5%
1990	25,921		9.8%
2000	31,287		20.7%
2010	37,816		20.9%
2020	41,135		8.8%
2023 (est.)	43,182		5.0%
U.S. Decennial Census 1790-1960 1900-1990 1990-2000 2010-2020

Isanti County, Minnesota - Demographic Profile
(NH = Non-Hispanic)

Race / Ethnicity	Pop 2010	Pop 2020	% 2010	% 2020
White alone (NH)	35,958	37,559	95.09%	91.31%
Black or African American alone (NH)	228	314	0.60%	0.83%
Native American or Alaska Native alone (NH)	163	201	0.43%	0.53%
Asian alone (NH)	302	488	0.80%	1.29%
Pacific Islander alone (NH)	12	13	0.03%	0.03%
Some Other Race alone (NH)	20	154	0.05%	0.41%
Mixed Race/Multi-Racial (NH)	517	1,510	1.37%	3.99%
Hispanic or Latino (any race)	582	5,308	1.54%	2.37%
Total	37,816	41,135	100.00%	100.00%

Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos can be of any race.

As of the census of 2000, there were 37,816 people, 14,331 households, and 8,415 families in the county. The population density was 86.7 per square mile (33.5/km). There were 12,062 housing units at an average density of 27.7 per square mile (10.7/km). The racial makeup of the county was 96.0% White, 0.6% Black or African American, 0.5% Native American, 0.8% Asian, 0% Pacific Islander, 1.6% from other races, and 0.94% from two or more races. 1.5% of the population were Hispanic or Latino of any race. 30.3% were of German, 21.3% Swedish, 12.7% Norwegian and 5.1% Irish ancestry.

There were 11,236 households, of which 38.1% had children under 18 living with them, 62.1% were married couples living together, 8.4% had a female householder with no husband present, and 25.1% were non-families. 20.1% of all households were made up of individuals, and 8.2% had someone living alone who was 65 or older. The average household size was 2.74 and the average family size was 3.15.

The county population contained 28.7% under 18, 7.8% from 18 to 24, 30.4% from 25 to 44, 22.2% from 45 to 64, and 10.8% who were 65 or older. The median age was 36. For every 100 females there were 100.5 males. For every 100 females age 18 and over, there were 98.8 males.

The median income for a household in the county was $50,127, and the median income for a family was $55,996. Males had a median income of $39,381 versus $26,427 for females. The per capita income for the county was $20,348. About 4.0% of families and 5.7% of the population were below the poverty line, including 5.7% of those under 18 and 8.6% of those 65 or older.

• Stanchfield

This rural turned exurban county is more conservative than the state as a whole. In 2008, John McCain won this county with almost 57% of the vote, while losing the state with 44% of the vote. Norm Coleman also did well, obtaining 48% of the vote while losing the state with 42%. Both George W. Bush and Tim Pawlenty won this county twice, winning a majority of the county each time.

Democrats tend to do poorly here. In 2008, Barack Obama obtained just 41% while he won the state with 54% of the vote. Al Franken received just 33% of Isanti County's votes. Since 1992, no Democrat has won this county with over 50% of the vote. In 2016, Donald Trump won almost 65% of the vote here while narrowly losing the state to Hillary Clinton. In 2020, Trump increased his vote share to just over 68%.

Independents also do well in this county. In 1998, the county's results were Jesse Ventura's best performance in the state, winning the county with over 50% of the vote. Ross Perot came in a close third place with 29% of the vote while getting 24% statewide.

United States presidential election results for Isanti County, Minnesota

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	18,027	69.55%	7,384	28.49%	507	1.96%
2020	16,491	68.05%	7,138	29.45%	606	2.50%
2016	13,635	64.88%	5,657	26.92%	1,724	8.20%
2012	11,675	57.75%	8,024	39.69%	518	2.56%
2008	11,324	56.47%	8,248	41.13%	481	2.40%
2004	11,190	57.94%	7,883	40.82%	240	1.24%
2000	7,668	51.36%	6,247	41.84%	1,014	6.79%
1996	4,450	34.35%	6,041	46.63%	2,464	19.02%
1992	3,988	29.84%	5,386	40.30%	3,992	29.87%
1988	5,246	45.81%	6,075	53.05%	131	1.14%
1984	5,660	50.91%	5,378	48.38%	79	0.71%
1980	4,480	41.45%	5,457	50.49%	872	8.07%
1976	3,159	33.55%	6,013	63.85%	245	2.60%
1972	3,715	48.66%	3,660	47.94%	259	3.39%
1968	2,429	38.33%	3,439	54.27%	469	7.40%
1964	1,982	32.93%	4,026	66.90%	10	0.17%
1960	3,067	53.86%	2,599	45.64%	28	0.49%
1956	2,348	47.35%	2,605	52.53%	6	0.12%
1952	2,682	52.16%	2,393	46.54%	67	1.30%
1948	1,918	38.41%	2,758	55.23%	318	6.37%
1944	2,205	49.14%	2,225	49.59%	57	1.27%
1940	2,617	48.82%	2,654	49.51%	90	1.68%
1936	1,437	28.05%	3,442	67.19%	244	4.76%
1932	1,484	30.43%	3,147	64.53%	246	5.04%
1928	3,137	71.13%	1,191	27.01%	82	1.86%
1924	1,588	39.54%	79	1.97%	2,349	58.49%
1920	3,007	67.57%	405	9.10%	1,038	23.33%
1916	1,123	48.18%	935	40.11%	273	11.71%
1912	314	14.54%	333	15.42%	1,513	70.05%
1908	1,198	58.47%	466	22.74%	385	18.79%
1904	1,603	84.06%	137	7.18%	167	8.76%
1900	1,525	72.69%	504	24.02%	69	3.29%
1896	1,490	66.52%	750	33.48%	0	0.00%
1892	728	52.11%	105	7.52%	564	40.37%

• National Register of Historic Places listings in Isanti County, Minnesota

• Minnesota DOT map of Isanti County

45°34′N 93°17′W / 45.56°N 93.29°W / 45.56; -93.29