John Penn was an Episcopalian.
His religious affiliation was classified as unknown by the North Carolina State Library. (Source: Ian Dorion, "Table of the Religious Affiliations of American Founders", 1997).
From: Robert G. Ferris (editor), Signers of the Declaration: Historic Places Commemorating the Signing of the Declaration of Independence, published by the United States Department of the Interior, National Park Service: Washington, D.C. (revised edition 1975), pages 117-118:
Unobtrusive and unassuming but remarkably efficient, likeable, and discreet, Penn quickly won the respect of his congressional colleagues. He rarely disputed with others, but when he did his good humor and peaceful manner saved the day. On one occasion, he feuded with President of Congress Henry Laurens of South Carolina over a personal matter. He accepted Laurens' challenge to a duel, but en route to the proposed site convinced Laurence that they should bury their differences and drop the matter...
Originally buried in the family graveyard adjacent to his home, his remains now rest in Guilford Courthouse National Military Park near Greensboro.
Note that numerous sources and authoritative references have been consulted in order to ascertain the religious affiliation of the American Founding Fathers. Note that the excerpts and references mentioned on this page are not the only references used in order to identify this person's religious affiliation.