Lyman Hall was a Congregationalist.
He was identified as a Congregationalist by: The Congregationalist Library and the Georgia Public Library Service. (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 65-67:
Lyman Hall was one of the four signers [of the Declaration of Independence] originally trained as ministers. He eventually found his pulpit in politics, though he had to preach vigorously to inspire the "congregation" of Georgia. He enthusiastically sparked the slow-developing independence movement there with George Walton and recruited Button Gwinnett, the third Georgia signer. Somehow Hall also managed to pursue careers as doctor, planter, and Governor.
A native of Wallingford, Conn., Hall was born in 1724. He graduated from Yale College in 1747 at the age of 23, returned home, and heeded a family call to the Congregational ministry. An uncle, Rev. Samuel Hall, trained him in theology. In 1749 he began preaching in Bridgeport and adjacent towns. Young and immature, he probably entrapped himself in the middle of a liberal-conservative schism and in some way alienated his congregation. But repentance brought quick reinstatement from dismissal in 1751, and for a couple of years he temporarily filled vacant pulpits.
During this period, in 1752, Hall married, but his wife lived only a year; about 2 years later he remarried, a union that was to bring forth a son. Meantime, Hall had become disillusioned by his ministerial experiences. He studied medicine with a local doctor, partially supporting himself by teaching. When his medical training was completed, he moved back to Wallingford and hung out his shingle.
In 1757 the 33-year-old Hall, seeking brighter fields, emigrated to Dorchester, S.C., a settlement of New England Puritans not far from Charleston. Within a few months, he joined some of the residents in a relocation that had been underway since 1752. They were pushing southward to Georgia's coastal Midway District, in St. John's Parish (present Liberty County)>
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.