There are several exclaves between the United States and Canada, including the entire state of Alaska (though the state can still be accessed by sea from the United States, except the small settlement of Hyder which is only accessible by road from British Columbia).
Several isolated territories exist between the U.S. and Canada, including the entire state of Alaska, although it can be reached by sea from the U.S., with the exception of the small town of Hyder, which is only accessible by land from British Columbia.