The position held by the defence was emphatically one to impose caution on the assailants.  To reach it the Confederates were confined to three roads, two from Mechanicsville, and one from Old Cold Harbour.  These roads led each of them through a broad belt of forest, and then, passing through open fields, descended into a winding valley, from five hundred to a thousand yards in breadth.  Rising near McGehee’s House, due south of Old Cold Harbour, a sluggish creek, bordered by swamps and thick timber, and cutting in places a deep channel, filtered through the valley to the Chickahominy.  Beyond this stream rose an open and undulating plateau, admirably adapted to the movement of all arms, and with a slight command of the opposite ridge.  On the plateau, facing west and north, the Federals were formed up.  A fringe of trees and bushes along the crest gave cover and concealment to the troops. 60 feet below, winding darkly through the trees, the creek covered the whole front; and in the centre of the position, east of New Cold Harbour, the valley was completely filled with tangled wood.

Towards Old Cold Harbour the timber on the Confederate side of the ravine was denser than elsewhere.  On the Federal left flank the valley of the Chickahominy was open ground, but it was swept by heavy guns from the right bank of the river, and at this point the creek became an almost impassable swamp.

Porter, who had been reinforced by 9000 men under General Slocum, now commanded three divisions of infantry, four regiments of cavalry, and twenty-two batteries, a total of 36,000 officers and men.  The morale of the troops had been strengthened by their easy victory of the previous day.  Their commander had gained their confidence; their position had been partially intrenched, and they could be readily supported by way of Alexander’s and Grapevine Bridges from the south bank of the Chickahominy.

The task before the Confederates, even with their superior numbers, was formidable in the extreme.  The wooded ridge which encircled the position afforded scant room for artillery, and it was thus impracticable to prepare the attack by a preliminary bombardment.  The ground over which the infantry must advance was completely swept by fire, and the centre and left were defended by three tiers of riflemen, the first sheltered by the steep banks of the creek, the second halfway up the bluff, covered by a breastwork, the third on the crest, occupying a line of shelter-trenches; and the riflemen were supported by a dozen batteries of rifled guns.* (* The remainder of the guns were in reserve.)