William Armstrong (23 December 1782-10 May 1865) was a member of the US House of Representatives (NR-VA 16) from 4 March 1825 to 3 March 1833, succeeding James Stephenson and preceding James M.H. Beale. Born in Lisburn, County Antrim, Ireland, he emigrated to America in 1792 and became postmaster of Paddytown, Virginia (now Keyser, West Virginia), a banker, a justice of the peace from 1820 to 1852, and a National Republican state delegate and congressman.