<Li> Ogdensburg--Prescott International Bridge--Ogdensburg, New York, and Johnstown, Ontario </Li> <Li> Three Nations Crossing--Cornwall, Ontario, and Massena, New York </Li> <P> The U.S. maintains immigration offices, called pre-clearance facilities, in eight Canadian airports with international air service to the United States (Calgary, Edmonton, Halifax, Montreal, Ottawa, Toronto, Vancouver, and Winnipeg). This expedites travel by allowing flights originating in Canada to land at a U.S. airport without being processed as an international arrival . Canada does not maintain equivalent personnel at U.S. airports due to the sheer number of U.S. departure locations with Canadian - bound flights and the limited number of flights compared to the number of U.S. - bound flights that depart major Canadian airports . </P> <P> Similar arrangements exist at major Canadian seaports that handle sealed direct import shipments into the U.S. </P>

On this map the border between canada and the united states is a