The American Philosophical Society (APS) is an American scholarly organization and learned society founded in 1743 in Philadelphia that promotes knowledge in the humanities and natural sciences through research, professional meetings, publications, library resources, and community outreach.

It was common at the time for intellectual societies to invite members from around the world, where the society recruited members from other countries, including Alexander von Humboldt, the Marquis de Lafayette, Baron von Steuben, Tadeusz Kościuszko, and Princess Dashkova.

[5] During this time, the society maintained a standing Committee on American Improvements; one of its investigations was to study the prospects for a canal to connect the Chesapeake Bay and the Delaware River.

[7] Following the American Revolutionary War, the society looked for leadership to Francis Hopkinson, one of the signatories of the United States Declaration of Independence.

Charles Darwin, Robert Frost, Louis Pasteur, Elizabeth Cabot Agassiz, John James Audubon, Linus Pauling, Margaret Mead, Woodrow Wilson, Maria Mitchell, and Thomas Edison were all prominent members of the society.

[17][18] A third floor was added in 1890 to accommodate the expanding library, but was removed in 1948–1950,[18] when the building was restored to its original appearance for the creation of Independence National Historical Park.

[19] In 2001, it was opened to the public as The American Philosophical Society Museum, hosting revolving, thematic exhibitions that explore intersections of history, art, and science.

The museum features works of art, scientific instruments, original manuscripts, rare books, natural history specimens, and curiosities of all kinds from the APS's own collections, along with objects on loan from other institutions.

APS restored the former Farmers' & Mechanics' Bank building at 425–29 Chestnut Street, which was built in 1854–55 to the design of John M. Gries in the Italianate style,[21] to serve as a lecture hall.