At Fort Necessity, the provision hut was depleted, and there was little shelter from the heavy rain that started to fall on the 2nd. With the rain, the trenches that Washington had ordered to be dug had turned into streams. Washington realized that he would have to defend against a frontal assault and also realized that it would be difficult because the woods were less than 100 yards away, within musket range, making it possible for a besieging attacker to pick off the defenders. To improve the defense, Washington ordered his men to cut trees down and to make them into makeshift breastworks.

Coulon arrived at Jumonville's Glen early on the morning of July 3. Horrified to find several scalped French bodies, he immediately ordered them to be buried. By 11:00 am on the 3rd of July 1754, Louis Coulon de Villiers came within sight of Fort Necessity. At this time, the Virginians were digging a trench in the mud. The pickets fired their muskets and fell back to the fort, whereupon three columns of Canadian soldiers and Indians advanced downhill towards the fort. As Coulon halted and then redeployed his troops, Washington began to prepare for an attack.

Coulon ordered his soldiers, led by Indians, to charge directly at Washington's line. Washington ordered the men to hold their ground and fire a volley. The Virginians, however, fled back to the fort, leaving Washington and the British regulars greatly outnumbered. Washington ordered a retreat back to the fort. Heavy rain began to fall that afternoon, and Washington's troops were unable to continue the firefight because their gunpowder was wet. As negotiations began, the Virginians, against Washington's orders, broke into the fort's liquor supply and got drunk.