Donop was the senior officer present in southern New Jersey in late 1776, and commanded the garrisons in Trenton, Burlington, and Bordentown, which consisted of several Hessian battalions, the Forty-second Highland Regiment (commanded by Colonel Stirling), and Jäger detachments. His main camp was at Bordentown prior to the Battle of Trenton, with one battalion occupying the town and the rest billeted along the country roads in Slabtown Black Horse [Columbus Burlington City and White House (the Mary Field Plantation). His overall commander was Major General James Grant. Donop wanted to absorb Colonel Johann Rall's brigade into his garrison to fortify Trenton, but William Howe was persuaded to let Rall hold command on his own in Trenton. Warned by local Loyalists of impending attack, Donop warned Grant, who dismissed these cautions.