The western half of New Guinea, retained by the Netherlands as a colony when it recognized Indonesian independence over the rest of the Dutch East Indies (27 December 1949) -- Indonesia claimed the territory as its own from the outset, making it a live sovereignty dispute throughout its existence. The Dutch pursued a separate 'Papuan' nation-building policy (a Nieuw-Guinea Raad/New Guinea Council was inaugurated 1961) distinct from Indonesia's, administered from the capital Hollandia (now Jayapura).
Ceded by the Netherlands under the New York Agreement (15 August 1962); administered by the UN Temporary Executive Authority (UNTEA) from 1 October 1962, then transferred to Indonesian administration 1 May 1963. Indonesian sovereignty was confirmed via the 1969 'Act of Free Choice' (a disputed, non-universal-suffrage vote endorsed by UN General Assembly Resolution 2504) -- the territory remains part of Indonesia today (as Papua/West Papua provinces), outside this atlas's current Oceania roster.
Open Library-verified (ISBN 9780824824709); the standard scholarly account of Dutch policy in New Guinea from 1949 through the 1962 transfer, directly on-topic.