Background
He was the son of Lieutenant John Allen McElwain (1743–1814) and Hannah (Melvin) McElwain (d 1853).
politician member of the New York State Senate
He was the son of Lieutenant John Allen McElwain (1743–1814) and Hannah (Melvin) McElwain (d 1853).
He was Sheriff of Genesee County from 1832 to 1834. He was Treasurer of Wyoming County from 1851 to 1853.
He was a member of the New York State Assembly (Genesee Company) in 1837. He was a member of the New York State Senate (30th Doctorate) in 1852 and 1853.