Illinois

Marion

37,729
2020 population
1830
first census record
20
census records

About Marion

Marion, Illinois, first appears in the United States federal census in 1830, when it recorded a population of 2,125. At the most recent census, in 2020, its population stood at 37,729.

Its recorded population peaked at 47,989 in 1940, and has since declined by roughly 21 percent.

On the ground today, 8 places are listed on the National Register of Historic Places.

Population by decade

Census YearPopulationChart
202037,729
201039,437
200041,691
199041,561
198043,523
197038,986
196039,349
195041,700
194047,989
193035,635
192037,497
191035,094
190030,446
189024,341
188023,686
187020,622
186012,739
18506,720
18404,742
18302,125
Source

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

Historic places in Marion

National Register of Historic Places listings in Marion, Illinois.

Badollet House
Salem
Methodist Episcopal Church
Salem
Bryan, William Jennings, Boyhood Home
Salem
Sentinel Building
Centralia
Illinois Central Railroad Water Tower and Pump House
Kinmundy
Bachmann, Charles and Naomi, House
Salem
Centralia Commercial Historic District
Centralia
Rohrbough, Calendar, House
Kinmundy

Other counties in Illinois

Explore census history and historic records for more Illinois counties.

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Everything a full report reveals about Marion County, Illinois

This page charts the census history of Marion County, Illinois. 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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Illinoishistory ›NRHP historic sites ›Notable people from Illinois›

Frequently asked about Marion

When does Marion first appear in the US census?
Marion, Illinois first appears in the federal census in 1830, with a recorded population of 2,125.
What is the population of Marion?
At the most recent federal census (2020), Marion had a recorded population of 37,729.
When did Marion's population peak?
Marion's recorded population peaked at 47,989 in 1940.
How many historic places are in Marion?
8 sites are listed on the National Register of Historic Places in Marion, Illinois.
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