The enemy had taken a strong natural position with most of the Grand Gulf garrison, numbering about seven or eight thousand men, under General Bowen.

His hope was to hold me in check until reinforcements under Loring could reach him from Vicksburg; but Loring did not come in time to render much assistance south of Port Gibson.

Two brigades of McPherson's corps followed McClernand as fast as rations and ammunition could be issued, and were ready to take position upon the battlefield whenever the 13th corps could be got out of the way.
The country in this part of Mississippi stands on edge, as it were, the roads running along the ridges except when they occasionally pass from one ridge to another.

Where there are no clearings the sides of the hills are covered with a very heavy growth of timber and with undergrowth, and the ravines are filled with vines and canebrakes, almost impenetrable.

This makes it easy for an inferior force to delay, if not defeat, a far superior one.
Near the point selected by Bowen to defend, the road to Port Gibson divides, taking two ridges which do not diverge more than a mile or two at the widest point.