The Mercer Oak was named after Hugh Mercer, a brigadier general in the Continental Army during the American Revolution. During the Battle of Princeton, Mercer was stabbed by an English soldier's bayonet. According to legend, he was unwilling to abandon his troops, and rested on the tree's trunk while they stood their ground. After the battle, Mercer was taken to the Clarke House where he died from his injuries nine days later.
On March 3, 2000, a wind storm felled the oak's last four branches. For public safety reasons, arborists cut off the remnants of the trunk the day after the tree fell. Following the tree's death, several scions from the tree were planted around the battlefield. In May 2000, an 8-foot sapling grown from a Mercer Oak acorn was planted inside the stump of the former tree.