College Hall is the oldest building on the West Philadelphia campus of the University of Pennsylvania. Prior to its construction, the university was located on Ninth Street in Center City, Philadelphia. The building was designed by Thomas Webb Richards and completed in 1873. The characteristic green color of the building is due to its composition of g…College Hall is the oldest building on the West Philadelphia campus of the University of Pennsylvania. Prior to its construction, the university was located on Ninth Street in Center City, Philadelphia. The building was designed by Thomas Webb Richards and completed in 1873. The characteristic green color of the building is due to its composition of green serpentine stone.