Ann Arbor Public Schools serves the city of Ann Arbor, Michigan and parts of eight surrounding townships covering 125 square miles (320 km²). The district operates 20 elementary schools, 1 K-8 open school, 5 middle schools, 3 comprehensive high schools, 3 alternative high schools, 3 preschools and 1 adult education program; the district maintains 640 acres (2.6 km²) of real estate and 3,300,000 square feet (310,000 m²) of building space.