Sumner's corps on the railroad, about 3 miles from the Chickahominy, connecting the right with the left; Keyes' corps on New Kent road, near Bottom's Bridge, with Heintzelman's corps at supporting distance in the rear.
The ford at Bottom's Bridge was in our possession, and the rebuilding of the bridge, which had been destroyed by the enemy, was commenced.
On the 22nd headquarters moved to Cold Harbor.
On the 26th the railroad was in operation as far as the Chickahominy, and the railroad bridge across that stream nearly completed.
When, on the 20th of May, our advanced light troops reached the banks of the Chickahominy River at Bottom's Bridge, they found that this, as well as the railroad bridge about a mile above, had been destroyed by the enemy. The Chickahominy in this vicinity is about 40 feet wide, fringed with a dense growth of heavy forest trees, and bordered by low, marshy bottom-lands, varying from half a mile to a mile in width.
Our operations embraced that part of the river between Bottom's and Meadow Bridges, which covered the principal approaches to Richmond from the east. Within these limits the firm ground lying above high-water mark seldom approaches near the river on either bank, and no locality was found within this section where the high ground came near the stream on both sides. It was subject to frequent, sudden, and great variations in the volume of water, and a rise of a few feet overflowed at almost any point, but during high water it rose above a fording stage, and could then be crossed only at the few points where bridges had been constructed. These bridges had all been destroyed by the enemy on our approach, and it was necessary not only to reconstruct these, but to build several others.
The west bank of river opposite the New and Mechanicsville Bridges was bordered by elevated bluffs, which afforded the enemy commanding positions to fortify, establish his batteries, enfilading the approaches upon the two principal roads to Richmond on our right, and resist the reconstruction of the important bridges. This obliged us to select other less exposed points for our crossings.
As the enemy was not in great force opposite Bottom's Bridge on the arrival of our left at that point, and as it was important to secure a lodgment upon the right bank before he should have time to concentrate his force and contest the passage, I forthwith ordered Casey's division to ford the river and occupy the opposite heights. This was promptly done on the 20th, and reconnaissance were at once pushed out in advance.
These troops were directed to throw up defenses in an advantageous position to secure our left flank. General Heintzelman's corps was thrown forward in support, and Bottom's Bridge immediately rebuilt.
In the mean time our center and right were advanced to the river above, and on the 24th we carried the village of Mechanicsville, driving the enemy out with our artillery, and forcing them across the bridge, force of they destroyed. General Naglee, on the same day, dislodged a force of the enemy from the vicinity of the "Seven Pines," on the Bottom's Bridge road, and our advance on the left secured a strong position near that place.