An exclave is strip of land that belongs to a political entity (like a country or a region) but that is not connected to it by land (islands are not counted). The strip of land is surrounded by other political entities. A good example is Kaliningrad Oblast (the region around the Russian city Kaliningrad). It belongs to the Russian Federation, but is separated from the rest of that country by territory belonging to Lithuania and Poland.
Although both meanings are close, an exclave might not be an enclave. An enclave is completely surrounded by one other country. For example, Kaliningrad is surrounded not by one state, but by two: Lithuania and Poland. It also borders the Baltic Sea. It is not an enclave. On the other hand, the Spanish exclave of Llívia is an enclave in France.
Many exclaves today have some sort of idea to become independent, especially if the exclave is far away from the Mainland.
A much more obscure use means, in medical discussion, a detached part of an organ, as of the pancreas, thyroid, or other gland.
The lists below are of various types of exclaves that are not enclaves.
The westernmost part of the state, a piece of land known as the Kentucky Bend, is surrounded on three sides by the Mississippi River, with Missouri on the opposite shore. Road access to the rest of Kentucky is only available by first going south into Tennessee. This exclave exists because the Mississippi, which forms the boundary between Missouri (right bank) and Kentucky/Tennessee (left bank), crosses latitude 36°30', which is part of the border between Kentucky and Tennessee, three times.
St. Martin Parish has an exclave which is separated from the main part of the parish by Iberia Parish.
Norfolk County is not in one piece. The towns of Brookline and Cohasset are part of Norfolk County, but are surrounded on all sides by other counties: Brookline by Suffolk and Middlesex, Cohasset by Plymouth.
The City and County of San Francisco has an exclave on Alameda Island, across San Francisco Bay and adjoining Alameda County. The exclave came into being as land on the border between the two counties was reclaimed from the Bay to build the Naval Air Station Alameda, now decommissioned. This small piece of open space cannot be reached from San Francisco (except by boat) without passing through Oakland and Alameda.
The "Lost Peninsula" in Monroe County, Michigan, can only be reached via Toledo, Ohio. It is surrounded by Maumee Bay in Lake Erie. (Map)
During World War II, Los Alamos County was created out of parts of Sandoval and Santa Fe Counties, for the convenience of the Manhattan Project. That portion of Sandoval County which is within the San Ildefonso Indian Reservation, about 3 km², became an exclave bounded by Los Alamos County on the southwest, Santa Fe County on the east and Rio Arriba County on the north.
Some territories are not geographically detached from their motherland. Nevertheless, they are more easily reached by entering a foreign country. Very often, this is because of their location in a hilly area. It may also be because the only road enters that foreign place before coming back to the mother country. These territories may be called "practical exclaves," "pene-exclaves" or "quasi-exclaves" and can be found along many borders, particularly those that are not heavily defended. They will only be attached to the motherland via an extremely small or thin slice of land.
St. Regis, Quebec: Part of the Akwesasne Mohawk Nation on the south shore of the Saint Lawrence River, it is attached by land to the St. Regis Mohawk Reservation in New York State; road access to the rest of Canada is only available through New York State.
The Northwest Angle is attached by land to the Canadian province of Manitoba; road access to the rest of the United States is only available through Manitoba
Point Roberts is at the southern end of a peninsula; land access to the rest of the United States is only available through the Canadian province of British Columbia
Carter Lake, a part of Pottawattamie County, Iowa, is surrounded by Omaha, Nebraska on three sides and the Missouri River on the fourth; road access to Iowa is only available through Nebraska.
The Upper Peninsula is attached by land to Wisconsin. It can be reached from the Lower Peninsula of Michigan by the 5 mile (8 km) long Mackinac Bridge.
Pentreheyling can only be reached by road through Wales.
later became part of Poland and Russia (see Kaliningrad above).