Before he entered Maryland he had assumed that the Federal garrisons at Winchester, Martinsburg, and Harpers Ferry would be cut off and abandoned without firing a shot (and, in fact, both Winchester and Martinsburg were evacuated).
Inden han rykkede ind i Maryland antog han at de føderale garnisoner i Winchester, Martinsburg og Harpers Ferry ville blive afskåret og opgivet uden at et skud ville blive løsnet (og rent faktisk blev såvel Winchester som Martinsburg evakueret).