Says wiki:

"The war started badly for the Americans as their attempts to invade Canada were repeatedly repulsed by General Isaac Brock commanding a small British force, composed largely of local militias and Native American allies."

"Despite years of warlike talk, the United States was unready to prosecute a war, for President Madison assumed that the state militias would easily seize Canada and negotiations would then follow."

"America's leaders had assumed that Canada could be easily overrun. Former President Jefferson optimistically referred to the conquest of Canada as "a matter of marching." Many Americans had migrated to Upper Canada and it was assumed (by both sides) they would favor the American cause. They did not. In Lower Canada, much more populous, support for Britain came from the English élite with strong loyalty to the Empire, and from the French élite who feared American conquest would destroy the old order by introducing Protestantism, anglicization, republican democracy, and commercial capitalism. The French habitants feared the loss to potential American immigrants of a shrinking acreage of good lands.[1]"

"American Brigadier General William Hull invaded Canada on July 12, 1812, from Detroit with an army mainly composed of militiamen. Once on Canadian soil, Hull issued a proclamation ordering all British subjects to surrender, or "the horrors, and calamities of war will stalk before you." He also threatened to kill any British prisoner caught fighting alongside an Indian. The proclamation helped stiffen resistance to the American attacks.

"Despite the threats, Hull's invasion turned into a retreat ... "

"A final attempt in 1812 by American General Henry Dearborn to advance north from Lake Champlain failed when his militia refused to advance beyond American territory. In contrast to the American militia, the Canadian militia performed well. French-Canadians, who found the anti-Catholic stance of most of the United States troublesome, and United Empire Loyalists, who had fought for the Crown during the American Revolutionary War, strongly opposed the American invasion. However, a large segment of Upper Canada's population was recent settlers from the United States who had no obvious loyalties to the Crown. Nevertheless, while there were some who sympathized with the invaders[2], the American forces found strong opposition from men loyal to the Empire."

"Late in 1813, after much argument, the Americans made two thrusts against Montreal. The plan eventually agreed upon was for Major-General Wade Hampton to march north from Lake Champlain ...

" ... On October 25, his 4,000-strong force was defeated at the Chateauguay River by Charles de Salaberry's force of fewer than 500 French-Canadian Voltigeurs and Mohawks."

Etc., etc.