Perelman Quadrangle, Philadelphia

Perelman Quadrangle, also known as Perelman Quad, is an area of the University of Pennsylvania's campus. The name was changed to Penn Commons in February 2018 amid sexual misconduct allegations. Perelman Quadrangle is centered around a plaza between Houston and College halls, but event spaces are located farther throughout Penn's campus.

Houston Hall (1895) is Penn's student union building, and by some definitions the first in the United States. Houston Hall was listed as a National Register of Historic Places contributing property in the University of Pennsylvania Campus Historic District in 1978. Houston Hall now contains a cafeteria and other eating establishments, study rooms, auditoriums, and numerous meeting rooms and offices.

Across the plaza is College Hall (1871), Penn's first building on its West Philadelphia and home to most classrooms and administrative space.

Also opening onto plaza are Claudia Cohen Hall (1874) and Irvine Auditorium (1932). Originally Logan Hall, Cohen Hall now houses administrative offices, meeting rooms, and several academic departments. It was built for the University's medical school and later was home to the dental school and later the Wharton School. The Irvine building contains a grand auditorium with a substantial pipe organ given by Cyrus Curtis, and also includes several smaller performance and rehearsal spaces. Williams Hall (1972), which houses offices and classrooms for humanities and language departments, also overlooks the plaza.