Sitaro Islands Regency (, although its formal name is Kabupaten Kepulauan Siau Tagulandang Biaro) is a regency located off the northern extremity of Sulawesi Island in the southern Sangihe Islands, North Sulawesi Province, Indonesia. The regency was formed under Law Number 15 Year 2007 from 2 January 2007 (), by separation from the Sangihe Islands Regency of which it had previously formed the southern part. The short form of the name is formed from one syllable from each of the names of the three principal islands — Siau, Tagulandang and Biaro.
The main island is Siau, while further south (nearer Sulawesi) are Tagulandang and Biaro. The regency's land area is 218.22 km2 and the total population was 63,801 at the 2010 censusBiro Pusat Statistik, Jakarta, 2011. and 71,817 at the 2020 census;Badan Pusat Statistik, Jakarta, 2021. the official estimate as at mid 2025 was 72,989 (comprising 36,746 males and 36,243 females).Badan Pusat Statistik, Jakarta, 27 February 2026, Kabupaten Kepulauan Siau Tagulandang Biaro Dalam Angka 2026 (Katalog-BPS 1102001.7108) Most of the population are fishermen and farmers. The religion of the majority of the population is Christianity, but there are also followers of Islam and Buddhism. The main town and administrative centre is Ondong, in West Siau.
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Administrative districts The regency is divided into ten districts (kecamatan), tabulated below with their areas and their populations at the 2010 census and 2020 census, together with the official estimates as at mid 2025.Badan Pusat Statistik, Jakarta, 27 February 2026, Kabupaten Kepulauan Siau Tagulandang Biaro Dalam Angka 2026 (Katalog-BPS 1102001.7108) The table also includes the locations of the district administrative centres, the number of administrative villages (totaling 83 rural desa and 10 urban kelurahan) in each district, and its postal codes.
Kode Wilayah Name ofDistrict(kecamatan) Areain km2 Pop'ncensus2010 Pop'ncensus2020 Pop'nestimatemid 2025AdmincentreNo.ofvillagesPostcodes 71.09.07 Biaro (a) 23.813,2483,7173,826Lumanggo595864 71.09.10 Tagulandang Selatan (South Tagulandang) 15.414,1714,8754,989Kisihang695866 71.09.03 Tagulandang (b) (West Tagulandang) 39.6911,59713,21513,338Balehumara15 (c) 95863 71.09.06 Tagulandang Utara (North Tagulandang) 14.774,0274,2064,259Bawoleu695865 71.09.05 Siau Barat Selatan (Southwest Siau) 12.344,0734,5844,613Mahuneni795868 71.09.04 Siau Timur Selatan (d) (Southeast Siau) 21.597,2838,5338,768Sawang1495867 71.09.02 Siau Barat (e) (West Siau) 16.187,8498,7998,922Paniki12 (f) 95862 71.09.09 Siau Tengah (Central Siau) 10.301,8502,0402,073Beong495860 71.09.01 Siau Timur (g) (East Siau) 41.1615,81617,61017,719Tarorane16 (h) 95861 71.09.08 Siau Barat Utara (i) (Northwest Siau) 22.973,8874,2384,482Hiung895869 Totals 218.2263,80171,81772,989Ulu Siau94
Notes: (a) including 20 small offshore islands. (b) including the offshore islands of Pulau Ruang (the fourth largest island in the regency, with an active volcano at its centre), Pulau Pasige and 2 smaller. (c) includes 2 kelurahan - Bahoi and Balehumara. (d) includes the small offshore island of Pulau Batuguhita. (e) includes the offshore islands of Pulau Makaleki and the small Pulau Batuhasaho. (f) includes 3 kelurahan - Ondong, Paniki and Paseng. (g) including the offshore islands of Pulau Pahepa, Pulau Gunatin, Pulau Mahoro and 13 smaller. (h) includes 5 kelurahan - Akesimbeka, Bahu, Bebali, Tarorane and Tatahadeng. (i) includes the offshore islands of Pulau Batupuki Sewenahe and Pulau Timuhe.
Climate Ondong, the seat of the regency has a tropical rainforest climate (Af) with heavy to very heavy rainfall year-round.
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