Although considered part of the Lake Champlain Islands, Alburgh, Vermont is not on an island. It is, in fact, a peninsula of land that extends southward from Quebec into Lake Champlain. The Alburgh Peninsula (also known as the Alburgh Tongue) has the distinction of being reachable by land only through Canada.
Alburgh shares this distinction with only two other places in the United States - Point Roberts, Washington, and the Northwest Angle in Minnesota. Unlike the other two cases, this isn’t really significant any more since there are bridges to provide access to the peninsula from within the United States. These bridges connect the town to Rouse’s Point, New York, West Swanton, Vermont and North Hero, Vermont.
There is a fourth bridge connecting Alburgh to Isle LaMotte, Vermont, but Isle LaMotte is an island without any other connection to land other than that bridge.
Province Point, Alburgh, Vermont
Just to the northeast of the east shore of Alburgh is the southernmost tip of a small promontory roughly 2 acres in size (45.013351°N 73.193257°W).The promontory is cut through by the US-Canadian border making the area an exclave of the United States contiguous with Canada.
An exclave is a territory legally or politically attached to a territory with which it is not physically contiguous. In this case Province Point is a part of the United States although it is not physically connected to the U.S.