[2][3] The PHMC administers the Historical Marker Program, which, when it began in 1914, installed metal plaques onto large rocks and boulders to commemorate individuals, events, and landmarks throughout the state.

Large cast aluminum markers were mounted on poles along a street or road, close to where a landmark was located, a person lived or worked, or an event occurred.

The commission is organized as an independent administrative board, including nine citizens of the Commonwealth appointed by the Governor, the state's Secretary of Education, two members of the Pennsylvania State Senate appointed by the President Pro Tempore and Minority Leader, and two members of the Pennsylvania State House of Representatives appointed by the Speaker and Minority Leader.

In March 2019, the chair was Nancy Moses, and the executive director was Andrea Lowery.

PHMC Commissioners as of March 2019 were: Ophelia M. Chambliss, Andy Dinniman, William V. Lewis, Robert Matzie, Fredrick C. Powell, Pedro Rivera, Robert M. Savakinus, Joseph B. Scarnati III, David Schuyler, Kenneth C. Turner, Parke Wentling, and Philip D. Zimmermann.