February 26, 1821, Concord, New Hampshire.
July 14, 1869, Providence County, Rhode Island.
Swan Point Cemetery, Providence, Rhode Island.
Leonard was the son of Richard and Sarah Damon Swain, and husband of Julia Maria Allen Swain. He was educated at Dartmouth College, Hanover, New Hampshire, and Andover Theological Seminary, Newton, Massachusetts. In 1847 he became a Congregational minister in Nashua, New Hampshire. In 1852 he became pastor of Central Church, Providence, Rhode Island.