Pierce Butler was an Episcopalian.
Pierce Butler should not be confused with the similarly named U.S. Supreme Court justice who served in the Supreme Court from 1923 until 1939.
He was identified as an Episcopalian by: A Worthy Company: Brief Lives of the Framers of the United States Constitution by M. E. Bradford and A History of Delaware Through its Governors 1776-1984 by Roger A. Martin. (Source: Ian Dorion, "Table of the Religious Affiliations of American Founders", 1997).
From: Robert G. Ferris (editor), Signers of the Constitution: Historic Places Commemorating the Signing of the Constitution, published by the United States Department of the Interior, National Park Service: Washington, D.C. (revised edition 1976), pages 151-152:
One of four signers born in Ireland, Butler was a British military officer turned South Carolina planter. He played a substantial role at the Constitutional Convention and afterward gained distinction in the U.S. Senate.
One of the most aristocratic delegates at the Convention, Butler was born in 1744 in County Carlow, Ireland. His father was Sir Richard Butler, Member of Parliament and a baronet...
Butler died [in Philadelphia] in 1822 at the age of 77 and was buried in the yard of Christ Church.
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.