The Second World War finally ended on September 2, 1945, and returning veterans caused Swarthmore College to open with its largest-ever enrollment of 1,018 students. At that time, Swarthmore’s optimal size was considered to be 700 resident and 50 day students, and after the initial round of dropouts, the count in April 1946 was 212 veterans in a student population of 870. The College had a severe shortage of student housing, but was able to take advantage of the Navy’s withdrawal from the former Mary Lyon School in March 1946. In July 1946, for $275,000, Swarthmore College purchased the Mary Lyon property from the owner banks, with the sale contingent on the Borough re-zoning the site from Residential to Apartment House District E.
The College thought the Mary Lyon buildings would be needed as student dormitories for about three years, after which time enrollment would drop to normal levels. The buildings on the west side of Harvard Avenue would then either be converted to apartments for faculty and the general public, or they would be demolished and replaced by a new apartment building. Four of the six buildings were converted in 1946 to house 19 faculty families and about 100 male students. Mary Lyon’s main classroom building, Miller-Crist, had only the one apartment, used by the Crist family, and that building was initially not put to any use by the College.
After the war, Pennsylvania State College operated twelve technical institutes, in which engineering technicians were trained in a 5-year program of night classes. The school could not keep up with the demand for graduates, and the course of instruction was changed to nine months of full-time day classes. The building in Chester that was then being used by Penn State for night classes was not available for day use, so in July 1947 Penn State leased from Swarthmore College the former Mary Lyon buildings Miller-Crist and Seven Gables, for use by technical and freshman students from Delaware County.
Seven Gables was the former Lillian Peters residence, between The Mary Leavitt and Miller-Crist, that had been the home of the elementary-level girls at Mary Lyon. Penn State called the Mary Lyon campus the Swarthmore Class Center, Swarthmore College called it the Penn State Center, and the sign in front of Miller-Crist read “The Pennsylvania State College Center.” The school was attended by 280 day students, and a somewhat greater number taking evening classes. They so clogged the nearby streets with their automobiles that Borough Council largely prohibited street parking in the neighborhood. The students were then allowed to park on the other side of Yale Avenue, below the Strath Haven Inn, on land owned by Swarthmore College.
There was some concern among the many Philadelphia-area colleges and universities that Penn State was encroaching on their turf, but the school kept its presence in the region even after leaving Mary Lyon. A court decision held that Abby Sutherland’s Ogontz School and Ogontz Junior College were not non-profit organizations, and that they were taxable. Rather than deal with that situation, she retired and in 1950 gave to Penn State the 11 buildings on 43 acres at Rydal, in Abington Township, that comprised the Ogontz campuses. Penn State left for Abington in 1951, and Swarthmore College’s vacant buildings at Mary Lyon then awaited their next tenant.