DeKalb is a city in DeKalb County, Illinois, United States. The population was 43,862 according to the 2010 census, up from 39,018 at the 2000 census. The city is named after decorated Franconian-French war hero Johann de Kalb, who died during the American Revolutionary War.
Founded in 1856, DeKalb became important in the development and manufacture of barbed wire, especially for agriculture and raising livestock. While agricultural-related industries remain a facet of the city, along with health and services, the city's largest employer in the 21st century is Northern Illinois University, founded in 1895. About 65 miles (105 km) from downtown Chicago, DeKalb is part of the Chicago metropolitan area.