The next operation for the 71st Regiment was at the Battle of Fort Washington in November 1776 followed by the Battle of Fort Lee later that month. The regiment went on to take part in the Philadelphia Campaign and saw action at the Battle of Brandywine in September 1777. A detachment of 71st Regiment under Captain Colin MacKenzie supported General John Burgoyne's operations along the Hudson River including the capture of Forts Clinton and Montgomery in October 1777.