Canada's geography complicated post-Civil-War invasion fears

How threatening was the veteran United States Army to British Canada after the Civil War?

Its size and experience were formidable, while Canada was difficult to invade and could combine determined local defence with British supplies arriving by sea.

Large veteran United States forces emerged from the Civil War, but numbers alone did not make Canada an easy conquest. Canada's hills and depth could absorb an invading army, while Canadian defenders had strong local and patriotic motives. Britain could continue bringing supplies by sea in a way the Confederacy had been unable to do. Canada retained contingency plans for operations against the United States into the twentieth century, which reflected prudent preparation rather than an expectation of war. Geography, resistance, logistics, and contingency planning all shaped the invasion risk.