The Columbia metropolitan area or Greater Columbia is a region with cultural and economic ties to Columbia, Missouri a city of 113,225 people. Boone County makes up the immediate Metropolitan statistical area while the addition of Audrain County and Randolph County form the Combined Statistical Area giving the area a population of 223,676 in 2014. The largest cities outside Columbia are Moberly, Mexico, Centralia, Vandalia and Ashland. The University of Missouri has a strong presence in the region. Interstate 70, and U.S. Highways 63, 54, 24, and 40 link the urban areas. The Missouri River forms the southwest border of the region.