DeKalb County is a county in the U.S. state of Indiana. As of the 2020 United States Census, the population was 43,265. The county seat is Auburn. On February 7, 1835, the Indiana State Legislature passed an omnibus bill that authorized the creation of thirteen counties in northeast Indiana on previously unorganized land. The organization of the coun…DeKalb County is a county in the U.S. state of Indiana. As of the 2020 United States Census, the population was 43,265. The county seat is Auburn. On February 7, 1835, the Indiana State Legislature passed an omnibus bill that authorized the creation of thirteen counties in northeast Indiana on previously unorganized land. The organization of the county's government commenced in 1837. It was named for General Johann de Kalb, a Continental Army officer from Bavaria, who was killed at the Battle of Camden in South Carolina. The first settlers in the future DeKalb County were from New England, settling what was then known as the Northwest Territory. These people were "Yankee" migrants, descended from the English Puritans who settled New England in the colonial era. In the 1870s immigrants from Ireland and Germany began arriving in DeKalb County, in large numbers.