While Lee was planning to have Jackson join him in an attack on McClellan's right flank, McClellan was planning an offensive of his own. McClellan had been very cautious throughout the entire campaign, but now he had finally decided to attack. He wanted to capture the high ground around what was called Oak Grove, part of the Seven Pines battlefield, so that he would have a better artillery position for a siege. The troops selected for the attack were the divisions of Joseph Hooker and Philip Kearny. Meeting them would be the Confederate division of Benjamin Huger.
The battle opened at 8:30 am on June 25th, 150 years ago today, with a Union advance. The Federals pushed through the wooded ground, which was intersected by branches of White Oak Swamp. Most of the line made progress, but the rightmost brigade under Daniel Sickles encountered heavier resistance, throwing the line out of order. Huger, sensing an opportunity, ordered a counterattack by the brigade of Ambrose Wright. One of his regiments wore colorful Zouave uniforms, which were more common on the Northern side. The Federals thought they were their own men, and did not fire until the last moment. The battle finally turned when the inexperienced 25th North Carolina delivered a perfect volley, breaking Sickles's brigade. Reinforcements were sent forward, and McClellan was notified of the reverse.
McClellan was not on the field, but he was trying to manage the battle by telegraph. Although he did not know the details of the fighting, he ordered the men back to their trenches around 10:30 am. However, when he arrived on the field a few hours later, he realized the fighting had not gone as badly as he had thought. He ordered the battle resumed at around 1:00 pm. The fighting continued until nightfall, the Federals trying to regain the ground they had won in the morning. By the end of the day McClellan's men gained around 600 yards at the cost of over 1,000 casualties on both sides. The battle did not continue the next day, for Robert E. Lee's plan would go into action, derailing McClellan's offensive prospects.