Mercer County is a

county A county () is a geographic region of a country used for administrative or other purposesL. Brookes (ed.) '' Chambers Dictionary''. Edinburgh: Chambers Harrap Publishers Ltd, 2005. in some nations. The term is derived from the Old French denoti ...

located in the northwestern portion of the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its so ...

Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...

. As of the 2020 census, the population was 3,538, making it the second-least populous county in Missouri. Its

county seat A county seat is an administrative center, seat of government, or capital city of a county or parish (administrative division), civil parish. The term is in use in five countries: Canada, China, Hungary, Romania, and the United States. An equiva ...

is Princeton. The county was organized February 14, 1845, and named for General John F. Mercer of the Revolutionary War.

History

Early years

Mercer County was organized February 14, 1845, from part of Grundy County. It is named in honor of General

Hugh Mercer Hugh Mercer (January 16, 1726 – January 12, 1777) was a Scottish brigadier general in the Continental Army during the American Revolutionary War. He fought in the New York and New Jersey campaign and was mortally wounded at the Battle of Pri ...

, who fought and died in the

American Revolutionary War The American Revolutionary War (April 19, 1775 – September 3, 1783), also known as the Revolutionary War or American War of Independence, was the armed conflict that comprised the final eight years of the broader American Revolution, in which Am ...

. The first permanent settlements in what is now Mercer County were in 1837, when a few families from other parts of Missouri moved to the area. James Parsons, a

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

native, is generally considered to be the first permanent settler, in the spring of 1837. The land was still included as part of Livingston County at that time and would remain so until 1841 when it would become part of the newly created Grundy County. Prior to 1837, the land was used by Native American tribes, primarily the Sac/Fox and

Potawatomi The Potawatomi (), also spelled Pottawatomi and Pottawatomie (among many variations), are a Native American tribe of the Great Plains, upper Mississippi River, and western Great Lakes region. They traditionally speak the Potawatomi language, ...

, as prime hunting grounds. The occasional temporary hunting village would be established by the tribes; otherwise, the land was devoid of humans. The town of Princeton, named for the battle where General Mercer was killed, was established as the county seat in 1847. The northern boundary of the county was in dispute for the first six years of its existence due to the Honey War, a bloodless territorial dispute between

and

Iowa Iowa ( ) is a U.S. state, state in the upper Midwestern United States, Midwestern region of the United States. It borders the Mississippi River to the east and the Missouri River and Big Sioux River to the west; Wisconsin to the northeast, Ill ...

. The boundary was 9.5 miles farther north than present day prior to an 1851 decision by the U.S. Supreme Court.

Civil War

Mercer County, like its neighbor to the east Putnam County, was a staunch supporter of the Union. Most county residents had roots in northern U.S. states "back east" like

Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

, and

Indiana Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...

, and did not have the strong slave-holding tradition of other northern Missouri counties like Macon, Audrain, and Monroe (commonly referred to as Little Dixie), whose population largely emigrated from Southern states. In the 1860 U.S. Census, only 12 Mercer County families were listed as slave owners, with a combined total of 24 slaves. Fewer than 20 Mercer County men fought for the Confederacy, while well over 1,000 volunteered for Union service. Among the units containing men from Mercer County were the 23rd, 27th and 35th Regiments, the 2nd and 12th Cavalry, the 5th Kansas Cavalry, and various smaller units of the Missouri State Militia. The 44th Missouri Infantry (USA), consisting of men from Mercer, Grundy, Sullivan, and other northwest Missouri counties, served a pivotal role in the Union victory at the Battle of Franklin, Tennessee, on November 30, 1864.

Geography

According to the U.S. Census Bureau, the county has a total area of , of which is land and (0.3%) is water.

Adjacent counties

* Decatur County, Iowa (northwest) *

Wayne County, Iowa Wayne County is a County (United States), county located in the U.S. state of Iowa. As of the 2020 United States census, 2020 census, the population was 6,497, making it the sixth-least populous county in Iowa. The county seat is Corydon, Iowa ...

(north) * Putnam County (east) * Sullivan County (southeast) * Grundy County (south) * Harrison County (west)

Major highways

* U.S. Route 65 * U.S. Route 136 * Missouri Route 145

Demographics

As of the

census A census (from Latin ''censere'', 'to assess') is the procedure of systematically acquiring, recording, and calculating population information about the members of a given Statistical population, population, usually displayed in the form of stati ...

of 2010, there were 3,785 people, 1,600 households, and 1,089 families residing in the county. The

population density Population density (in agriculture: Standing stock (disambiguation), standing stock or plant density) is a measurement of population per unit land area. It is mostly applied to humans, but sometimes to other living organisms too. It is a key geog ...

was . There were 2,125 housing units at an average density of . The racial makeup of the county was 98.72%

White White is the lightest color and is achromatic (having no chroma). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully (or almost fully) reflect and scatter all the visible wa ...

, 0.19%

Black Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ...

African American African Americans, also known as Black Americans and formerly also called Afro-Americans, are an Race and ethnicity in the United States, American racial and ethnic group that consists of Americans who have total or partial ancestry from an ...

, 0.56% Native American, 0.05%

Pacific Islander Pacific Islanders, Pasifika, Pasefika, Pacificans, or rarely Pacificers are the peoples of the list of islands in the Pacific Ocean, Pacific Islands. As an ethnic group, ethnic/race (human categorization), racial term, it is used to describe th ...

, 0.03% from other races, and 0.45% from two or more races. Approximately 0.29% of the population were

Hispanic The term Hispanic () are people, Spanish culture, cultures, or countries related to Spain, the Spanish language, or broadly. In some contexts, Hispanic and Latino Americans, especially within the United States, "Hispanic" is used as an Ethnici ...

or Latino of any race. There were 1,600 households, out of which 28.30% had children under the age of 18 living with them, 57.60% were

married couples Marriage, also called matrimony or wedlock, is a culturally and often legally recognised union between people called spouses. It establishes rights and obligations between them, as well as between them and their children (if any), and b ...

living together, 6.70% had a female householder with no husband present, and 31.90% were non-families. 29.30% of all households were made up of individuals, and 17.60% had someone living alone who was 65 years of age or older. The average household size was 2.31 and the average family size was 2.83. In the county, the population was spread out, with 23.00% under the age of 18, 6.70% from 18 to 24, 24.20% from 25 to 44, 24.00% from 45 to 64, and 22.00% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 95.70 males. For every 100 females age 18 and over, there were 92.60 males. The median income for a household in the county was $29,640, and the median income for a family was $35,313. Males had a median income of $26,690 versus $19,814 for females. The

per capita income Per capita income (PCI) or average income measures the average income earned per person in a given area (city, region, country, etc.) in a specified year. In many countries, per capita income is determined using regular population surveys, such ...

for the county was $15,140. About 10.20% of families and 13.30% of the population were below the

poverty line The poverty threshold, poverty limit, poverty line, or breadline is the minimum level of income deemed adequate in a particular country. The poverty line is usually calculated by estimating the total cost of one year's worth of necessities for ...

, including 13.30% of those under age 18 and 14.50% of those age 65 or over.

2020 Census

Religion

Education

North Mercer County R-III School District
- Mercer **North Mercer County Elementary School (PK-06) **Mercer High School (07-12)
Princeton R-V School District
- Princeton **Princeton Elementary School (PK-06) **Princeton High School (07-12)

Public libraries

*Mercer County Library

Communities

Cities

* Mercer * Princeton (county seat)

Village

* South Lineville

Census-designated place

* Ravanna

Other communities

* Mill Grove *

Modena Modena (, ; ; ; ; ) is a city and ''comune'' (municipality) on the south side of the Po Valley, in the Province of Modena, in the Emilia-Romagna region of northern Italy. It has 184,739 inhabitants as of 2025. A town, and seat of an archbis ...

Historical communities

SourceUSGenWeb: ''GNIS Query Results, Mercer County, Missouri''
/ref> *Adel *Alvord *Burrows *Cleopatra *Dinsmore *Goshen *Half Rock *Ilia *Saline *Topsy (Newtown) *Wataga

Townships

* Harrison * Lindley * Madison * Marion *

Medicine Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...

* Morgan * Ravanna *

Somerset Somerset ( , ), Archaism, archaically Somersetshire ( , , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by the Bristol Channel, Gloucestershire, and Bristol to the north, Wiltshire to the east ...

* Washington

Politics

Local

The Republican Party predominantly controls politics at the local level in Mercer County. Republicans hold all of the elected positions in the county. In the 2020 presidential election, Mercer County had the highest Republican turnout in the state of Missouri with greater than 86% of the population voting for Donald Trump.

State

All of Mercer County is a part of Missouri's 3rd District in the

Missouri House of Representatives The Missouri House of Representatives is the lower chamber of the Missouri General Assembly. It has 163 members, representing districts with an average size of 37,000 residents. House members are elected for two-year terms during general elections ...

and is represented b
Danny Busick
(R- Newtown). All of Mercer County is a part of Missouri's 12th District in the

Missouri Senate The Missouri Senate is the upper chamber of the Missouri General Assembly. It has 34 members, representing districts with an average population of 181,000. Its members serve four-year terms, with half the seats being up for election every two yea ...

and is currently represented b
Dan Hegeman
(R- Cosby).

Federal

All of Mercer County is included in Missouri's 6th Congressional District and is currently represented by Sam Graves (R- Tarkio) in the U.S. House of Representatives.

References

External links

Digitized 1930 Plat Book of Mercer County
from

University of Missouri The University of Missouri (Mizzou or MU) is a public university, public Land-grant university, land-grant research university in Columbia, Missouri, United States. It is Missouri's largest university and the flagship of the four-campus Univers ...

Division of Special Collections, Archives, and Rare Books {{coord, 40.42, -93.57, display=title, type:adm2nd_region:US-MO_source:UScensus1990 1845 establishments in Missouri Populated places established in 1845