The Pittsburgh History and Landmarks Foundation (PHLF) Historic Landmark plaque program was begun in 1968 in order to identify architecturally significant structures and significant pieces of Pittsburgh, Pennsylvania, United States's local heritage throughout Allegheny County.
Nominations are reviewed by the private non-profit foundation's Historic Plaque Designation Committee composed of trustees, architectural historians, and citizens.
Beginning in 2010, the committee expanded its program to consider applications for historic status from counties surrounding Allegheny, extending its reach to a 250-mile radius from the city, as long as the site has a connection to the greater Pittsburgh region.
Structures awarded the designation typically have aluminum or bronze plaques affixed to their exterior that signify their status.
Over 500 Historic Landmark Plaques have been awarded since the program's inception, although not all structures have been preserved.