'State of the Republic of Indonesia') was a federated state (negara bagian) of the United States of Indonesia (RUSI) which was established on 27 December 1949.

[1] The territory of the state included parts of Java and most of Sumatra, and its capital was Yogyakarta.

[2] The acting president of the Republic was Assaat (Sukarno became president of the RUSI)[3] and the prime minister was first Susanto Tirtoprodjo until 16 January 1950, then Abdul Halim.

[4] On 17 August, the United States of Indonesia ceased to exist as the last of the component states dissolved themselves into a unitary Republic of Indonesia encompassing the entire territory of the former Dutch East Indies except for West Papua.

[5][6] Assaat Datuk Mudo was the only president of this Yogyakarta-based republic