The majority of the PSU campus is located across a 50-acre (20 ha) section of southwest downtown Portland, in an area known as the University District. The campus is situated against the West Hills, and is bound by Clay Street to the north, Fourth Avenue to the east, Interstate 405 to the south, and 12th Avenue to the west. SW Broadway runs through the center of the campus, where the university's central buildings are located: Lincoln Hall, Cramer Hall, Smith Memorial Student Union, Fariborz Maseeh Hall, and Shattuck Hall; Cramer Hall, Smith Memorial, and Fariborz Maseeh Hall are connected by tunnels on the basement levels, as well as by skybridges on the upper levels, which allows students access between buildings without having to use street sidewalks.