The Historical Society of Pennsylvania

Specialty: Mid-Atlantic states’ economic, social and political history

Founded in 1824 in Philadelphia, The Historical Society of Pennsylvania is one of the oldest historical societies in the United States, holding many national treasures. The Society is one of the largest family history libraries in the nation. It has preeminent printed collections on Pennsylvania and regional history and offers superb manuscript collections renowned for their strength in 17th-, 18th-, and 19th-century history. With the addition of the holdings of The Balch Institute for Ethnic Studies in 2002, the Society has become a chief center for the documentation and study of the ethnic communities and immigrant experiences shared by people whose American history began more recently—between the late 19th century and our own times. Together these holdings, old and new, make the Society one of the nation’s most important special collections libraries.


The Society houses nearly 600,000 books, pamphlets, serials, and microfilm reels, 21 million manuscripts, and over 300,000 graphics items, making it one of the nation’s largest non-governmental repositories of documentary materials. Holdings include national treasures such as the first draft of the United States Constitution, an original printer’s proof of the Declaration of Independence, and the earliest surviving American photograph. But the true strength of the Society’s collection is the overall breadth and depth of materials that together offer a rich, complex portrait of U.S. history and society from the 17th century to the present.

The Society’s collections include a number of different types of materials: books and pamphlets; letters, diaries, account books, deeds, minutes, and scrapbooks; collections of personal papers created by individuals and families; records created by organizations and businesses; graphics; printed ephemera; and microforms.

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Image of Alfred Russell Wallace. Wallace was a contemporary of Charles Darwin and co-discoverer of the laws of natural selection, as well as the author of many books on evolutionary science. Image courtesy of the Historical Society of Pennsylvania.