Mackinac Island, and the Canadian
North West Company's trading post at
Sault Ste. Marie nearby were vital posts in the
fur trade, which dominated the economy and way of life of the Native American nations in the area known as the
Old Northwest. Most of the Native Americans were opposed to United States expansion and encroachment in the area. On 18 July 1812, a mixed force of British regular soldiers, Canadian voyageurs and Native Americans captured Mackinac Island in the
siege of Fort Mackinac before the American defenders knew that war had been declared between the United States and Britain. The news of this success influenced many more Native tribes who had previously been neutral or undecided to rally to the British cause, contributing to several more British victories over the next year. The British meanwhile abandoned their own defences at
St. Joseph Island and concentrated their forces at Mackinac Island. For the rest of the year and through much of 1813, the British hold on Mackinac was secure since they also held
Detroit, which the Americans would have to recapture before attacking Mackinac. Then on 10 September 1813, the Americans won the decisive naval
Battle of Lake Erie, which allowed them to recover Detroit and defeat the retreating British and Native force at the
Battle of the Thames. Although it was too late in the year to allow the Americans to mount an expedition to recover Mackinac before the lakes froze in winter, they had nevertheless cut the British supply lines to the post. The British garrison, commanded by Captain Richard Bullock of the
41st Regiment of Foot, were placed on half rations and also procured some fish and maize locally but were suffering severe shortages by the end of the winter.
British defences arrived to reinforce the crew of
HMS Nancy, a schooner vital to resupplying
Fort Mackinac. In February 1814, Lieutenant Colonel
Robert McDouall of the
Glengarry Light Infantry was ordered to re-establish communications with Mackinac and take charge of the post. McDouall's first task was to open a new supply line from
York via
Yonge Street and
Lake Simcoe to the
Nottawasaga River, which flows into
Georgian Bay. The Nottawasaga was selected in preference to the established post at
Penetanguishene on
Matchedash Bay, even though the navigation from the Nottwasaga was obstructed by rocks and shoals. However, the route from Lake Simcoe to Penetanguishene would need to be improved for , which would be almost impossible in the depths of winter, while the overland portage to the Nottawasaga was shorter and much more easily improved. McDouall's party consisted of ninety men of the
Royal Newfoundland Fencibles, most of whom were accustomed to serving as
marines, and eleven artillerymen with four field guns. He also brought with him twenty-one sailors of the
Royal Navy to reinforce the crew of the schooner
Nancy, which was being refitted at St. Joseph Island at the time, and thirty carpenters to assist in constructing thirty
batteaux. McDouall ordered the defences of the island to be strengthened. The existing fort was situated on a ridge which dominated the harbour on the south side of the island, but was itself overlooked by another wooded ridge, the highest point on the island. In 1812, the British had dragged artillery to this ridge to compel the fort to surrender. McDouall's troops built a stockade and blockhouse on the upper ridge, naming the new fortification
Fort George. Plans to rebuild the
Nancy as a gunboat were abandoned, and the
Nancy instead made two round trips between Mackinac Island and the Nottawasaga to carry supplies.
American plans established
Fort Gratiot in 1814 as an advanced base to retake
Mackinac Island. In 1814, the Americans attempted to retake the island as part of a larger campaign designed to sever the fur trading alliance between the British and the Natives in the northwestern states and territories. The
United States Secretary of the Navy,
William Jones, supported an attack on Mackinac as this would provide employment for the vessels of the American squadron on Lake Erie, which otherwise would have little further useful part to play in the war. The expedition to recover Mackinac was prepared at Detroit, and Brigadier General
Duncan McArthur established
Fort Gratiot at the southern end of Lake Huron as an advanced base.
William Clark, Governor of the
Missouri Territory, meanwhile led an expedition to establish a fort at
Prairie du Chien on the
Mississippi River. News that the Americans had occupied Prairie du Chien arrived at Mackinac on 21 June. McDouall was compelled to weaken his garrison by despatching an expedition under
William McKay (who held the local rank of Lieutenant Colonel) to recover the post. On 3 July, a squadron of five American brigs and gunboats under Commodore
Arthur Sinclair sailed from Detroit, carrying an embarked landing force of 700 soldiers under the command of Lieutenant Colonel
George Croghan. The force consisted of an
ad hoc battalion of regular infantry (made up of five detached companies of the 17th, 19th and 24th U.S. Infantry) under Major
Andrew Holmes and a battalion of volunteers from the
Ohio militia under Colonel William Cotgreave, with detachments of artillery. Rather than make directly for Mackinac, the American squadron first searched Matchedash Bay for the base from which the British at Mackinac were supplied, which the Americans thought was at Penetanguishene. As the weather was foggy and the Americans had no pilots familiar with the area, which abounded with islets and sunken rocks, they spent a week in the bay but found nothing. They then sailed to
St. Joseph Island, which had been the original British military post in 1812, but found it had been abandoned. They burned the empty post, and also the Canadian
North West Company trading post at
Sault Sainte Marie. The Americans finally arrived off Mackinac on 26 July. Their delayed arrival had given McDouall ample warning, and he had further reinforced his defences by calling in the last two companies of militia left to defend St. Joseph Island and Sault Ste. Marie. ==Battle==