Illinois

Jefferson

37,113
2020 population
1820
first census record
21
census records

About Jefferson

Jefferson, Illinois, first appears in the United States federal census in 1820, when it recorded a population of 691. At the most recent census, in 2020, its population stood at 37,113.

Its recorded population peaked at 40,045 in 2000, and has since declined by roughly 7 percent.

On the ground today, 2 places are listed on the National Register of Historic Places.

Population by decade

Census YearPopulationChart
202037,113
201038,827
200040,045
199037,020
198036,552
197031,446
196032,315
195035,892
194034,375
193031,034
192028,480
191029,111
190028,133
189022,590
188020,686
187017,864
186012,965
18508,109
18405,762
18302,555
1820691
Source

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

Historic places in Jefferson

National Register of Historic Places listings in Jefferson, Illinois.

Appellate Court, 5th District
Mount Vernon
Judd, C. H., House
Belle

Other counties in Illinois

Explore census history and historic records for more Illinois counties.

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Everything a full report reveals about Jefferson County, Illinois

This page charts the census history of Jefferson 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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Explore Illinois records

Illinoishistory ›NRHP historic sites ›Notable people from Illinois›

Frequently asked about Jefferson

When does Jefferson first appear in the US census?
Jefferson, Illinois first appears in the federal census in 1820, with a recorded population of 691.
What is the population of Jefferson?
At the most recent federal census (2020), Jefferson had a recorded population of 37,113.
When did Jefferson's population peak?
Jefferson's recorded population peaked at 40,045 in 2000.
How many historic places are in Jefferson?
2 sites are listed on the National Register of Historic Places in Jefferson, Illinois.
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