Lee’s Mill saw the first serious fighting during McClellan’s Peninsular Campaign of 1862 (American Civil War). Having landed his army at the tip of the peninsular formed by the James and York rivers, McClellan advanced towards Yorktown, expecting to find the Confederates in position around the town. Instead, he found them in a line across the entire peninsular, partly based on the Warwick River, which runs across the peninsular from south to north, reaching within a mile and a half of the northern shore of the Peninsular.
In 1862 it was a sluggish, boggy stream, about 20-30 yards wide, with a wider area of bogs, fringed by heavy woods. It was naturally a formidable barrier, but a series of dams along the river made it even more difficult to cross. Three of these had been constructed by the Confederate defenders of the line, while two were associated with mills.
At Lee’s Mills the dam was just upriver from a bridge, and protected by fortified positions on both sides of the river. However, these positions only contained three pieces of artillery, of which only one was to play any real part in the fighting. Despite this, McClellan judged the Confederate line to be too strong to risk an assault, and settled into a second siege of Yorktown.
The Union forces at Lee’s Mill were from the Second Division, Fourth Corps under Brigadier General William F. Smith. He had been ordered to reconnoitre a fort called ‘One-gun battery’. On the morning of 16 April he sent two Vermont regiments from his Second Brigade towards the Confederate position, with orders to open fire on any working parties. The infantry soon opened fire, and in return were shelled by the Confederate artillery. An artillery duel followed, between the Confederate guns around the dam and Captain Mott’s battery of the Third New York Artillery. Both sides suffered some losses in this firing, and the Confederates probably withdrew their gun from the east bank of the river at about this time. For most the day, their only field gun was a six pounder on the west bank of the river.
This fighting lasted for about an hour, and was over by noon, when McClellan arrived in person. He ordered Smith to hold his new position, near the Warwick River, and so Smith added his First Brigade to the forces near the river. An 18-gun bombardment began at around 3.00 p.m., followed by an attack led by two Vermont regiment. The aim of the attack was to discover if the Confederates had been forced to abandon their positions by the artillery. Instead, they had been reinforcing the position. Much of the Union ammunition had got wet during the river crossing, and the Union attack was pushed back across the river.
On the Confederate side, the preparations for this limited attack had looked much more formidable. Two thirds of an infantry division had massed in front of what had been a weakly held point. By the time the two Vermont regiments made their attack, they faced a force made up of parts of at least eight confederate regiments from McLaws’s division.
A final Union attack also failed to find a way across the river. Overnight, strong gun positions were built, the clossest only 300 yards from the Confederate lines. The action at Lee’s Mill was a minor skirmish in the context of the Peninsular, but in at least one regard it was typical of what was to come. The mid-afternoon attack had been approved by McClellan in person, but with a warning not to continue against heavy resistance. A more determined attack in force would have had a good chance of forcing its way across the river at what Magruder considered the weakest part of his line. Success at Lee’s Mills would have made the Confederate position at Yorktown untenable. Instead, the siege was to go on for another three weeks.
Lee’s Mill demonstrated the difficulty each side had in assessing the impact of battle. Magruder reported his losses as 75 killed and wounded, and estimated the Union losses as at least 600 killed and wounded. Meanwhile, Smith estimated his losses at around 150 (the actual figure was 35 killed, 121 wounded and 9 missing, for a total of 165).