The University of Wisconsin–Madison (University of Wisconsin, Wisconsin, UW, UW–Madison, or simply Madison) is a public land-grant research university in Madison, Wisconsin, United States. Founded when Wisconsin achieved statehood in 1848, UW–Madison is the official state university of Wisconsin and the flagship campus of the University of Wisconsin System. It was the first public university established in Wisconsin and remains the oldest and largest public university in the state. UW–Madison became a land-grant institution in 1866. The 933-acre (378 ha) main campus, located on the shores of Lake Mendota, includes four National Historic Landmarks. The university also owns and operates the 1,200-acre (486 ha) University of Wisconsin–Madison Arboretum, located 4 miles (6.4 km) south of the main campus, which is also a National Historic Landmark.