Canada – United States relations refers to the bilateral relations between the bordering countries of Canada and the United States . Relations between Canada and the United States historically have been extensive , given a shared border and ever-increasing close cultural , economical ties and similarities . The shared historical and cultural heritage has resulted in one of the most stable and mutually beneficial international relationships in the world . For both countries , the level of trade with the other is at the top of the annual combined import-export total . Tourism and migration between the two nations have increased rapport , but border security was heightened after the September 11 terrorist attacks on the United States in 2001 . The U.S. is approximately 9.25 times larger in population and has the dominant cultural and economic influence . Starting with the American Revolution , when anti-American Loyalists fled to Canada , a vocal element in Canada has warned against US dominance or annexation . The War of 1812 saw invasions across the border . In 1815 , the war ended with the border unchanged and demilitarized , as were the Great Lakes . The British ceased aiding First Nation attacks on American territory , and the United States never again attempted to invade Canada . Apart from minor raids , it has remained peaceful
September 11 terrorist attacks
September 11 attacks
Canada–United States relations