An enclave is a territory that is entirely surrounded by the territory of only one other state or entity. Such territory can be a small territory as part of a larger one. Enclaves may also exist within territorial waters. Enclave is sometimes used improperly to denote a territory that is only partly surrounded by another state. Many enclaves are also exclaves, but some are not, for example Vatican City and San Marino and Lesotho are completely enclaved sovereign states.

Vatican City, officially the Vatican City State, is a landlocked sovereign country, city-state, microstate, and enclave within Rome, Italy. It became independent from Italy in 1929 with the Lateran Treaty, and it is a distinct territory under "full ownership, exclusive dominion, and sovereign authority and jurisdiction" of the Holy See, itself a sovereign entity under international law, which maintains the city-state's temporal power and governance, diplomatic, and spiritual independence. The Vatican is also a metonym for the pope, Holy See, and Roman Curia.