In 1813 Britain had three forts on Lake Ontario to defend Upper Canada from American attack: Kingston, the main naval base, York (now Toronto), the provincial capital of Upper Canada, and Fort George on the western bank of the Niagara River, across the river from the American Fort Niagara. The main US naval base was at Sacket’s Harbor.
The Americans wanted to recapture Detroit and invade Canada, with an ultimate goal of taking Montreal. In order to do so they had to control Lake Erie, which in turn depended on conquering Ontario. The British were forced onto the defensive by lack of resources.
See this website for a map of the Lake Ontario theatre of operations.
In February the USA devised a plan to attack first Kingston and then York with 4,000 men from Sacket’s Harbor. These troops and 3,000 from Buffalo would then assault Fort George. There were probably only 2,100 British troops in Ontario, 600 of them at Kingston and 1,200 near the Niagara.
However, John Armstrong, just appointed US Secretary of War, thought that the British had 8-10,000 regulars in the area, more than there actually were in all of Canada. Consequently they abandoned their plan to attack Kingston. Henry Dearborn, the commander of US forces from the Niagara to the New England coast, thought that he faced 6-8,000 enemies troops. The Americans therefore decided not to attack Kingston, which left Sacket’s Harbor vulnerable to a British attack.
The weather meant that the US offensive could not start until late April. York was captured on 27 April. They spent three days loading as many stores and guns that they could carry and destroying what they could not carry. However, bad weather forced them to remain until 7 May. The next day the US squadron took the troops to Fort Niagara, before returning to Sacket’s Harbor.
On May 15 Colonel Winfield Scott was appointed Dearborn’s adjutant general. Scott, aided by Master Commandant Oliver Hazard Perry of the USN, organised an attack on Fort George. It began on 25 May with a bombardment from Fort Niagara. Commodore Isaac Chauncey’s naval squadron comprised a brig, a sloop and 12 gunboats
On 27 May 4,000 US troops landed in four waves. Brigadier General John Vincent’s defending force was outnumbered by about 3 to 1. He was forced to retreat, withdrawing 16 miles to Beaver Dams, where he ordered the British garrisons of Fort Erie and Chippewa to join him.
The abandonment of Fort Erie allowed Perry to move several US ships that had been trapped at Black Rock to Lake Erie. This took until 12 June because ships had to be dragged by oxen against the current.
On 25 May the British at Kingston learnt that Chauncey’s squadron and Dearborn’s army were at Fort George, so decided to attack Sacket’s Harbor. Lieutenant General Sir George Prevost, the Governor-General and C.in-C. of British North America was visiting Kingston, so took command.
The British had just completed HMS Wolfe, a sloop officially rated at 20 guns, but actually carrying one 24 pounder, eight 18 pounders, four 68 pound carronades and 10 32 pound carronades. This made Commodore James Lucas Yeo’s RN squadron on the Great Lakes slightly stronger than Chauncey’s American one, but the advantage would soon switch to the USN once the USS General Pike, armed with 28 24 pounders was completed.
The loss of Sacket’s Harbor would have deprived Chauncey of the General Pike and of his only shipyard. Most of Chauncey’s squadron was at Fort George, with only two schooners to face the British squadron of three sloops, two brigs and a schooner. The British invasion force consisted of about 800 men against about 1400-1500 defenders, but most of the British were regulars, whilst two-thirds of the Americans were militia.
As the British prepared to land on 27 May they saw a number of vessels also heading for the port. The invasion was halted because of the risk that it might be Chauncey’s squadron. In fact it was a number of US infantry heading to reinforce the garrison. Most of them were captured, but the delay allowed the Brigadier General Jacob Brown, a militia officer who commanded the US troops, to organise his defence.
The British landed early on 29 May. They initially forced the Americans back, but lacked the artillery to continue the attack once the Americans retreated into their fortifications. The larger British ships were unable to get close enough inshore to effectively fire on the fortification, so the British infantry was forced to withdraw. Brown’s report on the action stated that:
Had not General Prevost retreated most rapidly under the guns of his vessels, he would have never returned to Kingston.
Brown was given a commission as a Brigadier General in the regular army as reward for his efforts in the battle.
At one point the Americans, fearing defeat, set the General Pike alight. the fires were extinguished before serious damage could be done, but her completion was delayed until July.
At Fort George, Dearborn sent Brigadier General William H. Winder’s brigade, later joined by Brigadier General John Chandler’s brigade in pursuit of Vincent. The 3,400 US troops, commanded by Chandler as he was the senior of the two generals, camped at Stoney Creek on 5 June.
Guided by Billy Green, a local man who knew the terrain well, Vincent’s 700 men launched a night attack on the enemy in the early hours of 6 June. Lieutenant Colonel John Harvey had obtained the US password from a prisoner.
Surprise was lost because some of the British troops were too noisy. The Americans appeared to be in a strong position, but a mistake by Winder allowed the British to capture the guns and both himself and Chandler. The Americans, with their command structure disrupted and their firepower reduced, retreated.
The British established posts at Twelve Mile Creek and Beaver Dams, from which raiding parties were despatched. A US force of just over 500 men from the US 14th Infantry Regiment under Colonel Charles Boerstler was sent to deal with them.
It was tracked by Britain’s First Nation allies. Lieutenant James Fitzgibbon, commander of the 50 man garrison of Beaver Dams was warned by Laura Secord, who had learnt of the attack, probably by overhearing US officers billeted at her home talking of their plans. The direct journey from her home to Fitzgibbon’s HQ was 12 miles, but she took a treacherous 20 mile route, which took her 18 hours, in order to avoid US sentries.
On 24 June the Americans were ambushed in woods near Beaver Dams by 100 Mohawks and 300 Caughnawaga and some local militia. Fitzgibbon arrived and approached the Americans under a flag of truce, arguing that they were outnumbered and that he could not protect them from the First Nation warriors unless they surrendered. They did so, but only after more British troops appeared.
After Beaver Dams the US forces were reluctant to leave Fort George, but the British were too weak to retake it. Dearborn was dismissed on 6 July and given an administrative post in New York City.
 A. T. Mahan, Sea Power in Its Relations to the War of 1812, 2 vols. (London: Samson Low, Marston, 1905). vol. ii, pp. 15-19
 Quoted in Ibid. vol. ii, p. 23.