Urbana is the county seat of Champaign County, Illinois, United States. As of the 2010 census, the population was 41,250. Urbana is the tenth-most populous city in Illinois outside of the Chicago metropolitan area. According to the 2000 United States Census Bureau, the city had a total area of 10.5 square miles (27km2), of which 0.10% is water body. City planning maps from January 2010 indicate that the total area is now 11.7 square miles (30km2).