Knox was with Washington's army during the New York and New Jersey campaign, including most of the major engagements resulting in the loss of New York City. He narrowly escaped capture following the British invasion of Manhattan, only making it back to the main Continental Army lines through the offices of Aaron Burr. He was in charge of logistics in the critical crossing of the Delaware River that preceded the December 26, 1776 Battle of Trenton. Though hampered by ice and cold, with John Glover's Marbleheaders (14th Continental Regiment) manning the boats, he got the attack force of men, horses and artillery across the river without loss. Following the battle he returned the same force, along with hundreds of prisoners, captured supplies and all the boats back across the river by the afternoon of December 26. Knox was promoted to brigadier general for this accomplishment, and given command of an artillery corps expanded to five regiments. The army again crossed the river a few days later after the decision to make a stand at Trenton. Knox was with the army at the January 2, 1777 at the Battle of the Assunpink Creek, and again the next day at the Battle of Princeton.