Historical Society of Pennsylvania
Founded in 1824, the Historical Society of Pennsylvania is one of the country's oldest state historical societies. It holds an enormous collection of historical related-material dating from the 17th century to the present including 600,000 books, pamphlets, serials, and microfilm; 21 million manuscripts; and 300,000 graphic items (photographs, works on paper, watercolors, maps, etc.). The Society is also known for its impressive collection of ethnic and immigrant study materials, which it acquired when it merged with the Balch Institute 2002 and made an alliance with the Genealogical Society of Pennsylvania in 2006. There are a number of interesting and very important items in the collection such as the first draft of the Constitution, an original proof of the Declaration of Independence, and the earliest surviving American photograph.
Photo: Public Doman, via Wikimedia Commons