DeKalb County is a county located in the U.S. state of Illinois. As of the 2010 United States Census, the population was 105,160. Its county seat is Sycamore.
According to the US Census Bureau, the county has a total area of 635 square miles (1,640 km), of which 631 square miles (1,630 km) is land and 3.4 square miles (8.8 km) (0.5%) is water.
As of the 2010 United States Census, there were 105,160 people, 38,484 households, and 23,781 families residing in the county. The population density was 166.6 inhabitants per square mile (64.3/km). There were 41,079 housing units at an average density of 65.1 per square mile (25.1/km). The racial makeup of the county was 85.1% white, 6.4% black or African American, 2.3% Asian, 0.3% American Indian, 3.9% from other races, and 2.0% from two or more races. Those of Hispanic or Latino origin made up 10.1% of the population. In terms of ancestry, 32.6% were German, 17.5% were Irish, 8.7% were English, 7.0% were Polish, 6.4% were Italian, 6.3% were Swedish, and 3.8% were American.
Of the 38,484 households, 31.9% had children under the age of 18 living with them, 47.2% were married couples living together, 10.2% had a female householder with no husband present, 38.2% were non-families, and 25.8% of all households were made up of individuals. The average household size was 2.56 and the average family size was 3.11. The median age was 29.3 years.
The median income for a household in the county was $54,002 and the median income for a family was $70,713. Males had a median income of $50,192 versus $35,246 for females. The per capita income for the county was $24,179. About 7.7% of families and 14.6% of the population were below the poverty line, including 13.2% of those under age 18 and 4.5% of those age 65 or over.
DeKalb County Illinois neighborhoods include: Bridges of River Mist, Edens Garden, Ellwood, Fairview South, Fairway Oaks, Hidden Grove, Hillcrest Dr, Kensington Point, Maplewood, N 1st St, New Suburban, NIU Residential, Oak Crest, Overlook Point, South 1st Street, South Pointe, South Side, Stadium View, Sycamore Rd / Peace Rd, Taylor and First, The Knolls, Wineberry, W Lincoln Hy