An enclave is a territory (or a part of one) that is entirely surrounded by the territory of one other state.[1] Enclaves may also exist within territorial waters.[2]:60 Enclave is sometimes used improperly to denote a territory that is only partly surrounded by another state.[1] The Vatican City State and San Marino, both enclaved by Italy, and Lesotho, enclaved by South Africa, are completely enclaved sovereign states. An exclave is a portion of a state or territory geographically separated from the main part by surrounding alien territory (of one or more states).[3] Many exclaves are also enclaves, but are not necessarily so; an exclave can be surrounded by several states.[4] The Azerbaijani exclave of Nakhchivan is an example of an exclave that is not an enclave (bordering Armenia, Turkey and Iran).
Semi-enclaves and semi-exclaves are areas that, except for possessing an unsurrounded sea border (a coastline contiguous with international waters), would otherwise be enclaves or exclaves.[4]:116[5]:12–14 Enclaves and semi-enclaves can exist as independent states (Monaco, The Gambia and Brunei are semi-enclaves), while exclaves and semi-exclaves always constitute just a part of a sovereign state (like the Kaliningrad Oblast).[4]
A pene-exclave is a part of the territory of one country that can be conveniently approached—in particular, by wheeled traffic—only through the territory of another country.[6]:283 Pene-exclaves are also called functional exclaves or practical exclaves.[5]:31 Many pene-exclaves partially border their own territorial waters (i.e., they are not surrounded by other nations' territorial waters), such as Point Roberts, Washington and Minnesota's Northwest Angle. A pene-exclave can also exist entirely on land, such as when intervening mountains render a territory inaccessible from other parts of a country except through alien territory. A commonly cited example is the Kleinwalsertal, a valley part of Vorarlberg, Austria, that is accessible only from Germany to the north.
Examples include:
This arrangement is less common as highways are more easily re-aligned. Examples include: