Annexation

Annexation is the acquisition of new territory in which a state or other political entity declares its sovereignty over and takes possession of an area previously outside its borders. This may involve a period of military conquest, actual occupation, or the acquiescence of its inhabitants to a new authority. It is distinct from cession, in which one country gives up territory from another, and may occur with or without international acceptance of the change.

Annexation is often associated with a military victory, as had happened when the German Empire took over Alsace-Lorraine in 1871, but this is not always the case. For example, the occupation of Japan (1945-1952) did not make that nation a permanent part of the United States or one of its territories. Annexation also does not entail occupation: the government of Crimea, for instance, supported Russian sovereignty in 2014, and a disputed referendum indicated approval.