Before other British outposts had learned about Pontiac's siege at Detroit, Native Americans under Pontiac's plan captured five small forts in a series of attacks between May 16 and June 2.
The first to be taken was Fort Sandusky, a small blockhouse on the shore of Lake Erie. It had been built in 1761 by order of General Amherst, despite the objections of local Wyandots, who in 1762 warned the commander that they would soon burn it down. On May 16, 1763, a group of Wyandots gained entry under the pretense of holding a council, the same stratagem that had failed in Detroit nine days earlier. They seized the commander and killed the other 15 soldiers, as well as British traders at the fort. These were among the first of about 100 traders who were killed in the early stages of the war. The dead were ritually scalped and the fort—as the Wyandots had warned a year earlier—was burned to the ground.
Fort St. Joseph was captured on May 25, 1763, by the same method as at Sandusky. Potawatomis seized the commander and killed most of the 15-man garrison outright.
Fort Miami was the third fort to fall. On May 27, 1763, the commander was lured out of the fort by his Native mistress and shot dead by Miami Native Americans. The nine-man garrison surrendered after the fort was surrounded.
In the Illinois Country, Weas, Kickapoos, and Mascoutens took Fort Ouiatenon, on June 1, 1763. They lured soldiers outside for a council, and took the 20-man garrison captive without bloodshed. The Native Americans around Fort Ouiatenon had good relations with the British garrison, but emissaries from Pontiac at Detroit had convinced them to strike. The Natives apologized to the commander for taking the fort, saying that "they were obliged to do it by the other Nations." In contrast with other forts, the Natives did not kill the British captives at Ouiatenon.
The fifth fort to fall, Fort Michilimackinac, was the largest fort taken by surprise. On June 2, 1763, local Ojibwas staged a game of stickball with visiting Sauks. The soldiers watched the game, as they had done on previous occasions. The ball was hit through the open gate of the fort; the teams rushed in and were given weapons which Native women had smuggled into the fort. The Natives killed about 15 of the 35-man garrison in the struggle; later they killed five more in ritual torture.
Three forts in the Ohio Country were taken in a second wave of attacks in mid-June. Iroquois Senecas took Fort Venango around June 16, 1763. They killed the entire 12-man garrison outright, keeping the commander alive to write down the grievances of the Senecas. After that, they ritually burned him at the stake. Possibly the same Seneca warriors attacked Fort Le Boeuf on June 18, but most of the 12-man garrison escaped to Fort Pitt.
On June 19, 1763, about 250 Ottawa, Ojibwa, Wyandot, and Seneca warriors surrounded Fort Presque Isle , the eighth and final fort to fall. After holding out for two days, the garrison of about 30 to 60 men surrendered, on the condition that they could return to Fort Pitt. The warriors killed most of the soldiers after they came out of the fort.