Marking Time highlights one of the more than 2,500 markers that have been installed throughout the state since 1914 as part of the Pennsylvania Historical Marker Program, operated by PHMC's State Historic Preservation Office.

Greenbelt KnollGreenbelt Knoll was built in 1956 by Morris Milgram (1916-97), an award-winning leader of the open housing movement in the United States. Designed by the firm of Montgomery & Bishop, in association with architect Harry Duncan and landscape architect Margaret Lancaster Duncan, with Louis Kahn as a consultant, it was the first planned integrated housing development in Philadelphia and one of the earliest of its kind in the nation. Its rectilinear houses, accentuation of the existing landscape, and Midcentury Modern architecture mark it not only as one of the most important collections of Modernist buildings in Pennsylvania but also as a milestone in the American open housing and civil rights movements. It was a major accomplishment for Milgram, whose preeminent social cause was racial injustice. His crusade for integrated housing began in Hatboro, Montgomery County, where he worked in his father-in-law’s construction business. He encountered discrimination when an owner of one of his buildings questioned whether Milgram should sell to minorities. The incident enraged Milgram and he determined never again to build all-white housing. He reorganized the business that he inherited from his father-in-law and undertook construction of integrated housing only.

Milgram remained a civil rights activist throughout his life. In addition to projects in Pennsylvania, he went on to build integrated housing in Boston, Chicago and Princeton, New Jersey, as well as locations in six other states. In 1968 he was the first recipient of the National Human Rights Award of the Department of Housing and Urban Development. Among the organizations he established is the Fund for an Open Society in Philadelphia, beginning in 1975. With civil rights leader James Farmer Jr. as a cofounder and author James A. Michener as its honorary chairman, the fund helped people who moved to integrated housing obtain low-cost mortgages.

Milgram conceived Greenbelt Knoll with the support of black and white leaders who purchased a nine-acre tract within the city limits of Philadelphia surrounded by Pennypack Park. The 19 original residences were situated in natural wooded settings and are excellent examples of the organic vein of Midcentury Modern architecture. Now numbering 18, each house is unique, but together they form a homogeneous whole. There was a purposeful emphasis on preserving trees, with the street laid out to follow an existing winding dirt road. The homes were integrated into the landscape to create handsome outdoor spaces, yet achieve good orientation to allow desirable family privacy.

The first residents of Greenbelt Knoll included Robert N.C. Nix, the first African American U.S. Congressman from Pennsylvania; Rev. Leon Sullivan, internationally prominent black leader and founder of Opportunities Industrialization Centers of America; and Milgram himself. Milgram was adamant about creating integrated communities. To achieve this he developed a quota system in which 55 percent of homeowners were to be white and 45 percent nonwhite. He developed another housing community around the same time in Trevose, Bucks County, with the same quota system. Over time the Trevose community has transitioned to one that is primarily black. Interestingly, Greenbelt Knoll remains integrated in numbers that are much in keeping with their original percentages.

The residents of Greenbelt Knoll have continued Milgram’s intention of integration because they support the notion themselves. Several of the white residents who remain or come back to visit Greenbelt Knoll recall discrimination they faced as children in school because they lived among other races. At that time it was a revolutionary idea to live in an integrated community. Still, the residents take pride in rising above the discrimination they faced and embrace their close-knit heterogeneous community. In honor of the neighborhood’s 50th anniversary, some of the residents launched an effort to obtain recognition for this unique housing development. Nominations for both the Historical Marker Program and the National Register of Historic Places were submitted, and both were successful.


Karen Galle is on the staff of PHMC’s Bureau for Historic Preservation and has been the coordinator of the Pennsylvania Historical Marker Program since 2005. Previously she worked for 10 years in the agency’s former Commonwealth Conservation Center.