The Ann Arbor campus is separated into four main areas: the North, Central, Medical, and South Campuses. There are more than 500 large buildings, with a more than 29 million square feet (664 acres or 2.69 km²). The Central and South Campuses are next to each other, while the North Campus area is separated from them by the Huron River. An East Medical Campus has been built on Plymouth Road, with some university-owned buildings.