Ohio

Mercer

42,528
2020 population
1820
first census record
21
census records

About Mercer

Mercer, Ohio, first appears in the United States federal census in 1820, when it recorded a population of 95. At the most recent census, in 2020, its population stood at 42,528.

The county's recorded population has risen across the decades to its highest level in 2020.

On the ground today, 18 documented military engagements have been recorded within the county, among them St. Clair's Defeat (Battle of the Wabash, Nov 1791), St. Clair's Defeat — Initial Attack (Nov 4, 1791), St. Clair's Defeat — Multiple columns, and 30 places are listed on the National Register of Historic Places.

Population by decade

Census YearPopulationChart
202042,528
201040,814
200040,924
199039,443
198038,334
197035,265
196032,559
195028,311
194026,256
193025,096
192026,872
191027,536
190028,021
189027,220
188021,808
187017,254
186014,104
18507,712
18408,277
18301,110
182095
Source

Population data from the United States decennial census, U.S. Census Bureau (public domain).

Battles & engagements in Mercer

Military engagements that took place in Mercer, Ohio.

St. Clair's Defeat (Battle of the Wabash, Nov 1791)
1791
St. Clair's Defeat — Initial Attack (Nov 4, 1791)
1791
St. Clair's Defeat — Multiple columns
1791
Battle of the Wabash (St. Clair's Defeat)
1791
St. Clair's Defeat November 4 1791
1791
St. Clair's Defeat
1791
Northwest Indian War — Capture of Fort Recovery Dec 1793
1793
Skirmish at Fort Recovery Advance
1793
Battle of Fort Recovery (June 1794)
1794
Battle of Fort Recovery Second Fight 1794
1794
Battle of Fort Recovery (Ohio)
1794
Battle of Fort Recovery — First Attack (June 30, 1794)
1794
Battle of Fort Recovery — Second Attack (July 1, 1794)
1794
Fort Recovery Supply Column Attack (June 30, 1794)
1794
Battle of Fort Recovery
1794
Battle of Fort Recovery – Confederacy Attack
1794
Battle of Fort Recovery June 30 1794
1794
Skirmish at Fort Recovery
1812

Historic places in Mercer

National Register of Historic Places listings in Mercer, Ohio.

Fort Recovery Site
Fort Recovery
Chickasaw School and Rectory
Chickasaw
Immaculate Conception Catholic Church Complex
Celina
St. Henry Catholic Church
St. Henry
Gruenwald Convent
Cassella
Wallischeck Homestead
Fort Recovery
St. Rose Catholic Church Complex
St. Rose
Grand Lake St. Marys Lighthouse
Celinda
Gast, Matthias, House and General Store
Maria Stein
Cassella Catholic Church and Rectory
Cassella
St. Charles Seminary and Chapel
Carthagena
St. Aloysius Catholic Church
Carthagena
St. Anthony Catholic Church, Padua
St. Anthony
Maria Stein Catholic Church and Rectory
Maria Stein
Maria Stein Convent
Maria Stein
St. Sebastian Catholic Church and Rectory
St. Sebastian
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Other counties in Ohio

Explore census history and historic records for more Ohio counties.

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Everything a full report reveals about Mercer County, Ohio

This page charts the census history of Mercer County, Ohio. A full Aubrey report for an address here pulls together everything the historical record holds about the ground, from the earliest settlement to the twentieth century:

Overview
An interactive map of the location with historic sites, battles and Native heritage plotted, and its full story era by era.
The Land
The historic sites and place names around the location, and how this land was settled and used.
Geology
The bedrock beneath the site, its age and rock type, reaching back millions of years.
LiDAR Terrain
Laser-scanned terrain that reveals earthworks and old features hidden in the landscape.
Conflict & War
The battles, raids and skirmishes fought near here, across every era of American conflict.
The Civil War
The Civil War on this ground, 1861 to 1865: who held it, and the battles, camps and regiments nearby.
The Soldiers
The men who marched from here in the Civil War, named and traced where the record allows.
Native Heritage
The Native nations who held this land, mapped across time from before European contact to today.
Settlement
Who claimed and held this ground, from Indigenous homelands through the colonial powers to the United States.
The Community
How the town grew, who came, and what kind of place it became, traced through the census record.
Rivers & Rail
The rivers, canals and railroads that connected this place between 1830 and 1911.
Notable People
The people born, buried or genuinely tied to this exact place, with their stories.
Historical Maps
Historic maps of the location layered over how it looks today.
Finds & Access
Museum objects tied to the area, and the laws on searching, collecting and access here.
Literature
The old books, county histories and archives that mention this place, quoted with their sources.
Spotlight
A deep dive into the most remarkable, lesser-known history of the place, traced back to the record.
Points of Interest
The most significant historic sites and landmarks near the location, and why they matter.
Timeline
The whole story of the location told era by era, from first peoples to the present day.
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Frequently asked about Mercer

When does Mercer first appear in the US census?
Mercer, Ohio first appears in the federal census in 1820, with a recorded population of 95.
What is the population of Mercer?
At the most recent federal census (2020), Mercer had a recorded population of 42,528.
Were any battles fought in Mercer?
18 documented military engagements took place in Mercer, including St. Clair's Defeat (Battle of the Wabash, Nov 1791), St. Clair's Defeat — Initial Attack (Nov 4, 1791), St. Clair's Defeat — Multiple columns.
How many historic places are in Mercer?
30 sites are listed on the National Register of Historic Places in Mercer, Ohio.
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