The Bacan Islands, formerly also known as the Bachans, Bachians, and Batchians, are a group of islands in the Moluccas in Indonesia. They are mountainous and forested, lying south of Ternate and southwest of Halmahera. The islands are administered by the South Halmahera Regency of North Maluku Province. They formerly constituted the Sultanate of Bacan.
Bacan (Batjan), formerly also known as Bachian or Batchian, is the group's largest island. The second and third-largest islands are Kasiruta and Mandioli. Bacan Island in 2020 included about 82,387 people, of which about 10,000 live in the capital Labuha; it is subdivided into seven districts. Kasiruta and Mandioli each have over 11,000 inhabitants, and each is subdivided into two districts. A fourth island, Bacan Lomang, forms a twelfth district within the group. There are dozens of smaller islands in the group, which had a total population of 84,075 at the 2010 Census, but by the 2020 Census had risen to 111,517. The official estimate as at mid 2022 was 115,612.
The group is divided into twelve administrative districts (kecamatan) out of the thirty districts within South Halmahera Regency. They are tabulated below with their areas and their populations at the 2010 Census and 2020 Census, together with the official estimate for mid 2022. The table also includes the number of administrative villages (desa and kelurahan) in each district and its post code.
From early times, Bacan was one of the four kingdoms of Maluku together with Ternate, Tidore and Jailolo. The ruling elite converted to Islam in about the late 15th century. The sultan at first resided on Kasiruta Island and had political and commercial influence in northern Ceram and the Papuan Islands. In 1513, the first Portuguese trading fleet to reach the Moluccas set up a trading post on Bacan which at the time was tied to the Sultan of Ternate by dynastic marriages. The fleet's commander, Captain Antonio de Miranda Azevedo, left seven men on Bacan to buy cloves for the following year's expedition.