Martin County is a county in Minnesota, United States. As of the 2020 census, the population was 20,025. Its county seat is Fairmont.

The county was created by the Minnesota Territory legislature on May 23, 1857, with Fair Mount (which was also platted in 1857) designated as county seat. The town's name was later shortened to Fairmont. Two explanations have been advanced for the county's name. A delegate to the US Congress from the Wisconsin Territory, Morgan Lewis Martin, introduced the legislative act to organize the Minnesota Territory. But in 1904 the county's oldest residents attested that the name referred to Henry Martin, an early settler from Connecticut who ran several businesses during the pre-territory era.

Martin County lies on Minnesota's border with Iowa. The East Fork of the Des Moines River flows southeastward through the lower western part of the county. The county terrain consists of low rolling hills, dotted with lakes and ponds, completely devoted to agriculture where possible. The terrain slopes to the east and north, with its highest point near its southwest corner, at 1,407 ft (429 m) ASL. The county has an area of 730 square miles (1,900 km), of which 712 square miles (1,840 km) is land and 17 square miles (44 km) (2.4%) is water.

• Fairmont Municipal Airport (FRM)

Historical population

Census	Pop.	Note	%±
1860	151		—
1870	3,867		2,460.9%
1880	5,249		35.7%
1890	9,408		79.2%
1900	16,936		80.0%
1910	17,518		3.4%
1920	21,085		20.4%
1930	22,401		6.2%
1940	24,656		10.1%
1950	25,655		4.1%
1960	26,986		5.2%
1970	24,316		−9.9%
1980	24,687		1.5%
1990	22,914		−7.2%
2000	21,802		−4.9%
2010	20,840		−4.4%
2020	20,025		−3.9%
2023 (est.)	19,657		−1.8%
U.S. Decennial Census 1790-1960 1900-1990 1990-2000 2010-2020

Martin County Racial Composition

Race	Num.	Perc.
White (NH)	17,947	89.62%
Black or African American (NH)	112	0.6%
Native American (NH)	32	0.16%
Asian (NH)	92	0.46%
Pacific Islander (NH)	6	0.03%
Other/Mixed (NH)	516	2.6%
Hispanic or Latino	1,320	6.6%

As of the census of 2000, there were 21,802 people, 9,067 households, and 6,047 families in the county. The population density was 30.6 per square mile (11.8/km). There were 9,800 housing units at an average density of 13.8 per square mile (5.3/km). The racial makeup of the county was 97.22% White, 0.25% Black or African American, 0.10% Native American, 0.42% Asian, 0.02% Pacific Islander, 1.26% from other races, and 0.73% from two or more races. 1.93% of the population were Hispanic or Latino of any race. 51.6% were of German, 11.9% Norwegian, 5.9% Swedish and 5.0% English ancestry.

There were 9,067 households, out of which 29.80% had children under the age of 18 living with them, 56.60% were married couples living together, 7.20% had a female householder with no husband present, and 33.30% were non-families. 30.00% of all households were made up of individuals, and 15.20% had someone living alone who was 65 years of age or older. The average household size was 2.35 and the average family size was 2.92.

The county population contained 24.80% under the age of 18, 6.40% from 18 to 24, 24.90% from 25 to 44, 24.00% from 45 to 64, and 19.90% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 95.30 males. For every 100 females age 18 and over, there were 91.50 males.

The median income for a household in the county was $34,810, and the median income for a family was $44,541. Males had a median income of $30,467 versus $21,780 for females. The per capita income for the county was $18,529. About 7.10% of families and 10.50% of the population were below the poverty line, including 15.10% of those under age 18 and 9.00% of those age 65 or over.

Martin County has been reliably Republican for almost its entire existence. It has voted Republican in 35 of the 41 elections since the formation of the county and has only voted Democratic once since 1948.

United States presidential election results for Martin County, Minnesota

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2020	7,480	67.94%	3,305	30.02%	224	2.03%
2016	7,062	67.06%	2,733	25.95%	736	6.99%
2012	6,657	60.69%	4,054	36.96%	257	2.34%
2008	6,053	56.29%	4,413	41.04%	288	2.68%
2004	6,311	57.13%	4,590	41.55%	146	1.32%
2000	5,686	54.83%	4,166	40.17%	519	5.00%
1996	4,303	40.91%	4,718	44.86%	1,496	14.22%
1992	4,438	38.23%	4,019	34.62%	3,152	27.15%
1988	5,724	53.34%	4,922	45.87%	85	0.79%
1984	7,308	60.67%	4,673	38.80%	64	0.53%
1980	7,057	57.40%	4,301	34.98%	936	7.61%
1976	6,484	51.92%	5,672	45.42%	332	2.66%
1972	7,569	64.59%	3,816	32.57%	333	2.84%
1968	7,115	59.43%	4,271	35.67%	587	4.90%
1964	6,529	53.84%	5,575	45.98%	22	0.18%
1960	8,479	66.81%	4,194	33.04%	19	0.15%
1956	8,152	71.16%	3,289	28.71%	15	0.13%
1952	9,411	77.63%	2,673	22.05%	39	0.32%
1948	4,662	43.31%	6,015	55.88%	87	0.81%
1944	5,182	53.68%	4,443	46.02%	29	0.30%
1940	6,409	59.79%	4,290	40.02%	21	0.20%
1936	3,090	31.45%	6,492	66.08%	243	2.47%
1932	3,004	38.26%	4,731	60.26%	116	1.48%
1928	5,110	64.10%	2,822	35.40%	40	0.50%
1924	4,238	56.24%	751	9.97%	2,546	33.79%
1920	5,142	78.46%	1,221	18.63%	191	2.91%
1916	1,741	47.16%	1,756	47.56%	195	5.28%
1912	578	17.46%	1,141	34.47%	1,591	48.07%
1908	1,922	59.05%	1,054	32.38%	279	8.57%
1904	2,167	70.66%	656	21.39%	244	7.96%
1900	1,819	54.69%	1,233	37.07%	274	8.24%
1896	1,739	54.31%	1,327	41.44%	136	4.25%
1892	1,189	57.22%	661	31.81%	228	10.97%
1888	1,161	64.68%	471	26.24%	163	9.08%
1884	736	62.43%	260	22.05%	183	15.52%
1880	863	81.96%	190	18.04%	0	0.00%
1876	634	79.85%	160	20.15%	0	0.00%
1872	685	81.45%	156	18.55%	0	0.00%
1868	520	83.74%	101	16.26%	0	0.00%
1864	190	91.79%	17	8.21%	0	0.00%
1860	40	86.96%	6	13.04%	0	0.00%

County Board of Commissioners

Position		Name	District	Next Election
	Commissioner	Elliot Belgard	District 1	2024
	Commissioner	Jaime Bleess	District 2	2026
	Commissioner and Vice Chair	Kathy Smith	District 3	2024
	Commissioner and Chairperson	Richard Coons	District 4	2026
	Commissioner	Steven Flohrs	District 5	2024

State Legislature (2018-2020)

Position		Name	Affiliation	District
	Senate	Julie Rosen	Republican	District 23
	House of Representatives	Bob Gunther	Republican	District 23A

U.S Congress (2018-2020)

Position		Name	Affiliation	District
	House of Representatives	Brad Finstad	Republican	1st
	Senate	Amy Klobuchar	Democrat	N/A
	Senate	Tina Smith	Democrat	N/A

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

• William H. Budd, History of Martin County: A True and Complete History of the County from its Earliest Settlement Down to 1880. Fairmont, MN: The Independent, 1897.
• Roscoe C. Hunt, "Pioneer Physicians of Martin County Prior to 1900," Minnesota Medicine, vol. 25, no. 10 (Oct. 1942) and vol. 25, no. 11 (Nov. 1942).
• Ray F. Kesler, Service Record Book of Men and Women of World War II, Martin County. Fairmont, MN: n.p., n.d. [1950s].
• Martin County Historical Society, Martin County, 1857-1932: Diamond Jubilee Celebration and Homecoming, Fairmont, Minnesota, June 26 to July 4, 1932. Fairmont, MN: Martin County Historical Society, 1932.
• Martin County Home Council, Martin County's Heritage. Fairmont, MN.: Martin County Extension Home Council, 1972–1976.
• Allen L Moore, Historical Narrative of Martin County, Before 1850. Fairmont, MN: Martin County Historical Society, 1932.
• Arthur M. Nelson, Know Your Own County: A History of Martin County, Minnesota. Fairmont, MN: Martin County Historical Society, 1947.
• Arthur M. Nelson, Martin County Men in the Great War, 1917-1919. Fairmont, MN: Sentinel Publishing Co., 1920.
• Sentinel, A Pictorial History of Martin County, MN. Marceline, MO: Heritage House, 1992.

• Martin County government’s website

43°41′N 94°34′W / 43.68°N 94.56°W / 43.68; -94.56