Illinois

DeKalb

100,420
2020 population
1840
first census record
19
census records

About DeKalb

DeKalb, Illinois, first appears in the United States federal census in 1840, when it recorded a population of 1,697. At the most recent census, in 2020, its population stood at 100,420.

Its recorded population peaked at 105,160 in 2010, and has since declined by roughly 5 percent.

On the ground today, 6 documented military engagements have been recorded within the county, among them Battle of Stillman's Run, Black Hawk War — Battle of Stillman's Run, Indian Creek Massacre.

Population by decade

Census YearPopulationChart
2020100,420
2010105,160
200088,969
199077,932
198074,624
197071,654
196051,714
195040,781
194034,388
193032,644
192031,339
191033,457
190031,756
189027,066
188026,768
187023,265
186019,086
18507,540
18401,697
Source

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

Battles & engagements in DeKalb

Military engagements that took place in DeKalb, Illinois.

Battle of Stillman's Run
1832
Black Hawk War — Battle of Stillman's Run
1832
Indian Creek Massacre
1832
Stillman's Run
1832
Stillman's Run (Black Hawk War)
1832
Battle of Stillman's Run (May 1832)
1832

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Everything a full report reveals about DeKalb County, Illinois

This page charts the census history of DeKalb 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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Frequently asked about DeKalb

When does DeKalb first appear in the US census?
DeKalb, Illinois first appears in the federal census in 1840, with a recorded population of 1,697.
What is the population of DeKalb?
At the most recent federal census (2020), DeKalb had a recorded population of 100,420.
When did DeKalb's population peak?
DeKalb's recorded population peaked at 105,160 in 2010.
Were any battles fought in DeKalb?
6 documented military engagements took place in DeKalb, including Battle of Stillman's Run, Black Hawk War — Battle of Stillman's Run, Indian Creek Massacre.
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