Illinois Counties
Illinois County map
Click Image to Enlarge

Illinois Counties

There are one hundred and two counties in Illinois. St. Clair County was the first county established in what is today Illinois. Most counties in Illinois were named after early American leaders, especially of the American Revolutionary War, as well as soldiers from the Battle of Tippecanoe and the War of 1812.

DeKalb County, Illinois

DeKalb County Education, Geography, and HistoryDeKalb County, Illinois Courthouse

DeKalb County is a county located in the state of Illinois. Based on the 2010 census, the population was 105,160. DeKalb county was created on March 4, 1837. The county seat is Sycamore. The county is named for Johann de Kalb (1721-1780), German soldier in the Continental Army who fought alongside Gilbert du Motier, marquis de Lafayette.

DeKalb County is part of the Chicago-Naperville-Elgin, IL-IN-WI Metropolitan Statistical Area.

Etymology - Origin of DeKalb County Name

The county is named for Johann DeKalb, a German baron, who served in the Colonies during the Revolution, and was mortally wounded at Camden, South Carolina in 1780.


County QuickFacts: CensusBureau Quick Facts

DeKalb County History

DeKalb County was created on March 4, 1837 (Laws, 1837, p. 97) and was formed from Kane County. Present area, or parts of it, formerly included in: Kane County (1836-1837), LaSalle County (1831-1835), Putnam County (1825-1831), Fulton County (1823-1825), Pike County (1821-1823), Clark County (1819-1821), Crawford County (1816-1819), Edwards County (1815-1816), Madison County (1812-1815) and St. Clair County (1795-1812).

The County was named for Johann de Kalb, a German baron, who served in the Colonies during the Revolution, and was mortally wounded at Camden, South Carolina in 1780. The County Seat is Sycamore . Prior County Seats was Orange- Name later changed to Sycamore (1837-1839), Coltonville (1839-1840) and Sycamore (1840-Present).

Geography: Land and Water

As reported by the Census Bureau, the county has a total area of 635 square miles (1,645 km2), of which 634 square miles (1,642 km2) is land and 1 square mile (2 km2) (0.13%) is water.

DeKalb county is located in north Illinois. Kishwaukee River State Fish and Wildlife Area and Shabbona Lake State Park are found in this county.

Neighboring Counties

Bordering counties are as follows:

  • North: Boone County
  • Northeast: McHenry County
  • East: Kane County
  • Southeast: Kendall County
  • South: La Salle County
  • Southwest: Lee County
  • Northwest: Ogle County; Winnebago County


Compare More Colleges and Universities
Find the Right School

Find more schools to match to your needs.

County Resources
US Counties
Click Image to Enlarge