 Upon his release, Morris returned to Peekskill where he discovered that he had been promoted to the rank of captain while in the custody of the British. Morris commanded a company back to White Plains until he received orders to head south to Virginia. Upon arrival, Morris's company, under the overall command of General George Washington, aided in Siege of Yorktown, the last major battle of the American Revolution. Specifically, Morris's company of light infantry provided support to the forlorn hope commanded by Colonel Alexander Hamilton.
