Morton Pennypacker

Frank Knox Morton Pennypacker (1872–1956) was a collector of Long Island, New York historical material and author of several books on Long Island history, including "George Washington's Spies," the story of the Culper Ring.

Born in Pennsylvania, Pennypacker moved to New York City a little after the turn of the 20th century before moving to Southampton, New York on Long Island.

A writer and publicist by trade, he made a private hobby of collecting historical materials related to Long Island which eventually amounted to what is today called the Long Island Collection (formerly known as the Morton Pennypacker Long Island Collection), which contains some 20,000 odd books, papers, manuscripts, pictures, and other documents pertaining to the history of Long Island.

He is credited as the discoverer of the true identity of "Samuel Culper, Junior", the head spy of the Culper Ring, as Robert Townsend (spy), a member of the renowned New York Townsend family. Pennypacker did so by identifying an exact match in penmanship between the Culper letters attributed to Culper Junior and letters written by Robert Townsend.

The Collection is housed in the East Hampton Library. Pennypacker died at the age of 84.