Born: May 15, 1816, Suffield, Connecticut.
Died: November 23, 1895, New Haven, Connecticut.
Buried: Grove Street Cemetery, New Haven, Connecticut.
Sylvanus was the son of Israel and Mercy Phelps, husband of Sophia Emelia Linsley, and father of Arthur Phelps. Occasionally, his name is shown as Samuel
D. Phelps.
He attended the Connecticut Literary Institute; Brown University, Providence, Rhode Island (graduated 1844); and Yale Divinity School, New Haven, Connecticut.
After ordination, he pastored at the First Baptist Church in New Haven (1854–82), and the Jefferson Street Baptist Church, Providence, Rhode Island (1876)
Later, he became editor of The Christian Secretary. His son was preacher, author and professor William Lyons Phelps.