johnston consulted with the local commander, brig. gen. john gregg, and learned that only about 6,000 troops were available to defend the town. johnston ordered the evacuation of jackson, but gregg was to defend jackson until the evacuation was completed. by 10 a.m., both union army corps were near jackson and had engaged the enemy. rain, confederate resistance, and poor defenses prevented heavy fighting until around 11 a.m., when union forces attacked in numbers and slowly but surely pushed the enemy back. in mid-afternoon, johnston informed gregg that the evacuation was complete and that he should disengage and follow.