Mason County is a county located in the U.S. state of Michigan. As of the 2020 Census, the population was 29,052. The county seat is Ludington.

Mason County comprises the Ludington, MI Micropolitan Statistical Area.

The county is named for Stevens T. Mason, Governor of Michigan from 1835 to 1840. It was created by the Michigan Legislature in 1840 as Notipekago County, then renamed Mason County in 1843. The county was administered by Ottawa County prior to the organization of county government in 1855.

According to the US Census Bureau, the county has a total area of 1,242 square miles (3,220 km), of which 495 square miles (1,280 km) is land and 747 square miles (1,930 km) (60%) is water.

• US 10 – runs east–west through central part of county. Runs from Ludington through Amber, Scottville, Custer, and Branch.
• US 31 – enters Mason County at 2 miles (3.2 km) east of SW corner; runs north to intersect US-10 near Ludington. Runs concurrent with US-10 east for 5 miles (8.0 km), then runs north. Exits county at 4 miles (6.4 km) east of NW corner of county.
• M-116 – runs NW from Ludington along shoreline of Lake Michigan to Ludington State Park.
• 
  Bus. US 31 is a business spur running east of Ludington.

• USBR 35 enters Mason County from Pentwater; has a concurrency with USBR 20; proceeds north into Manistee County
• USBR 20 begins (until near future) at SS Badger with US 10; has a concurrency with USBR 35; goes through Freesoil; proceeds east into Lake County; proceeds east for about 310 miles to Marine City

By land

• Manistee County – north
• Lake County – east
• Newaygo County – southeast
• Oceana County – south

By water

• Sheboygan County, Wisconsin – southwest
• Manitowoc County, Wisconsin – west

• Manistee National Forest (part)

Historical population

Census	Pop.	Note	%±
1850	93		—
1860	831		793.5%
1870	3,263		292.7%
1880	10,065		208.5%
1890	16,385		62.8%
1900	18,885		15.3%
1910	21,832		15.6%
1920	19,831		−9.2%
1930	18,756		−5.4%
1940	19,378		3.3%
1950	20,474		5.7%
1960	21,929		7.1%
1970	22,612		3.1%
1980	26,365		16.6%
1990	25,537		−3.1%
2000	28,274		10.7%
2010	28,705		1.5%
2020	29,052		1.2%
2023 (est.)	29,159		0.4%
US Decennial Census 1790–1960 1900–1990 1990–2000 2010–2018

As of the 2000 United States Census, of 2000, there were 28,274 people, 11,406 households, and 7,881 families in the county. The population density was 57 people per square mile (22 people/km). There were 16,063 housing units at an average density of 32 per square mile (12/km). The racial makeup of the county was 95.84% White, 0.73% Black or African American, 0.78% Native American, 0.28% Asian, 0.02% Pacific Islander, 0.82% from other races, and 1.53% from two or more races. 3.01% of the population were Hispanic or Latino of any race. 24.5% were of German, 10.4% Polish, 8.8% English, 8.5% Irish, 7.7% American and 5.0% Swedish ancestry. 96.0% spoke only English, while 2.2% spoke Spanish at home.

There were 11,406 households, out of which 29.70% had children under the age of 18 living with them, 56.40% were married couples living together, 9.20% had a female householder with no husband present, and 30.90% were non-families. 26.50% of all households were made up of individuals, and 11.70% had someone living alone who was 65 years of age or older. The average household size was 2.43 and the average family size was 2.92.

The county population contained 24.20% under the age of 18, 7.10% from 18 to 24, 26.20% from 25 to 44, 25.80% from 45 to 64, and 16.80% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 97.50 males. For every 100 females age 18 and over, there were 94.40 males.

The median income for a household in the county was $34,704, and the median income for a family was $41,654. Males had a median income of $33,873 versus $22,616 for females. The per capita income for the county was $17,713. About 8.20% of families and 11.00% of the population were below the poverty line, including 16.50% of those under age 18 and 7.00% of those age 65 or over.

Mason County has usually voted Republican in national elections. Since 1884, the county's voters have selected the Republican Party nominee in 83% (30 of 36) of the national elections through 2024.

United States presidential election results for Mason County, Michigan

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	10,830	59.86%	6,973	38.54%	288	1.59%
2020	10,207	59.06%	6,802	39.36%	274	1.59%
2016	8,505	57.50%	5,281	35.70%	1,006	6.80%
2012	7,580	51.69%	6,856	46.75%	229	1.56%
2008	7,147	46.89%	7,817	51.29%	277	1.82%
2004	8,124	55.60%	6,333	43.34%	154	1.05%
2000	7,066	54.29%	5,579	42.86%	371	2.85%
1996	5,066	41.35%	5,597	45.69%	1,588	12.96%
1992	5,102	39.00%	4,829	36.91%	3,151	24.09%
1988	6,800	59.58%	4,531	39.70%	82	0.72%
1984	8,202	67.83%	3,803	31.45%	87	0.72%
1980	7,137	58.14%	4,134	33.68%	1,005	8.19%
1976	6,812	59.15%	4,541	39.43%	163	1.42%
1972	6,811	63.57%	3,697	34.50%	207	1.93%
1968	5,311	54.02%	3,660	37.23%	860	8.75%
1964	3,842	39.02%	5,993	60.87%	11	0.11%
1960	6,011	58.21%	4,305	41.69%	10	0.10%
1956	6,142	65.15%	3,274	34.73%	12	0.13%
1952	6,179	64.65%	3,298	34.51%	81	0.85%
1948	4,147	55.99%	2,988	40.34%	272	3.67%
1944	4,446	58.27%	3,137	41.11%	47	0.62%
1940	4,874	55.62%	3,836	43.77%	53	0.60%
1936	3,224	39.37%	4,598	56.14%	368	4.49%
1932	3,098	42.48%	3,854	52.85%	340	4.66%
1928	4,318	72.74%	1,567	26.40%	51	0.86%
1924	3,567	67.18%	815	15.35%	928	17.48%
1920	3,652	69.39%	1,338	25.42%	273	5.19%
1916	2,198	53.17%	1,689	40.86%	247	5.97%
1912	844	21.51%	1,073	27.34%	2,007	51.15%
1908	2,577	65.71%	1,132	28.86%	213	5.43%
1904	2,394	72.13%	764	23.02%	161	4.85%
1900	2,185	61.31%	1,251	35.10%	128	3.59%
1896	2,177	56.27%	1,580	40.84%	112	2.89%
1892	1,426	45.85%	1,383	44.47%	301	9.68%
1888	1,697	50.79%	1,573	47.08%	71	2.13%
1884	1,299	50.49%	1,217	47.30%	57	2.22%

Mason County operates the county jail, maintains rural roads, operates the major local courts, records deeds, mortgages, and vital records, administers public health regulations, and participates with the state in the provision of social services. The county board of commissioners controls the budget and has limited authority to make laws or ordinances. In Michigan, most local government functions – police and fire, building and zoning, tax assessment, street maintenance etc. – are the responsibility of individual cities and townships.

(information as of Jan 2021)

• Ludington (county seat)
• Scottville

• Custer
• Fountain
• Free Soil

• Pere Marquette Charter Township

• Branch (partially)
• Chapple Corners
• Fairview
• Fern
• Ferryville
• Tallman
• Walhalla

• The Little River Band of Ottawa Indians, a federally recognized Odawa Native American tribe, occupies a small reservation of approximately 740 acres (2.99 km) within Custer Township. The tribe also occupy another reservation within Brown Township just north in Manistee County.

The West Shore Educational Service District, based in Ludington, services the districts in the county along with those of Lake and Oceana. The intermediate school district offers regional special education and general education services, as well as technical career programs for its students.

Mason County is served by the following regular public school districts:

• Ludington Area School District
• Mason County Central Schools
• Mason County Eastern Schools

The county also has one charter school, the Gateway to Success Academy.

Mason County has the following private schools:

• Covenant Christian School (Non-denominational)
• Ludington Area Catholic School (Catholic)

• List of Michigan State Historic Sites in Mason County, Michigan
• Mason County Courthouse
• Mason County District Library
• National Register of Historic Places listings in Mason County, Michigan

• Mason County Press
• Mason County Website
• Mason County History Companion
• Mason County Michigan History and Directory
• Mason County Memories

44°01′N 86°30′W / 44.02°N 86.50°W / 44.02; -86.50