| Official Name: | Samosir Regency |
| Native Name: | (Kabupaten Samosir) |
| Native Name Lang: | id |
| Type: | Regency |
| Motto: | Satahi Saoloan (Agreed Agreed) |
| Subdivision Type: | Country |
| Subdivision Name: | Indonesia |
| Subdivision Type1: | Province |
| Subdivision Name1: | North Sumatra |
| Seat Type: | Regency seat |
| Seat: | Pangururan |
| Leader Title: | Regent |
| Leader Name: | Vandiko Gultom |
| Leader Title1: | Vice Regent |
| Leader Name1: | Martua Sitanggang |
| Leader Title2: | Chairman of Council of Representatives |
| Leader Name2: | Saut Martua Tamba (PDI-P) |
| Leader Title3: | Vice Chairmen of Council of Representatives |
| Leader Name3: | Nasib Simbolon (National Awakening Party) and Basrun Sihombing (Nasdem) |
| Area Total Km2: | 1444.25 |
| Population As Of: | mid 2023 estimate |
| Population Total: | 141333 |
| Population Density Km2: | auto |
| Population Footnotes: | [1] |
| Timezone1: | WIB |
| Utc Offset1: | +7 |
thumb|right|Resort in Ambarita, Samosir Regencythumb|right|Batak Toba House in Simanindo, Samosir Regencythumb|right|Tomok Market, Samosir Regency
Samosir Regency is an inland regency in North Sumatra. It was created on 18 December 2003 by splitting away the western districts of the former Toba Samosir Regency. The regency covers a land area of 1,444.25 square kilometres, including the whole of Samosir Island in the inland sea of Lake Toba. It had a population of 119,653 at the 2010 census[2] and 136,441 at the 2020 Census;[3] the official estimate for mid 2023 was 141,333 - comprising 70,648 males and 70,685 females.[4] Its administrative seat is the town of Pangururan on the west coast of Samosir Island.
The regency is divided administratively into nine districts (kecamatan), tabulated below with their areas and their populations at the 2010 Census[5] and the 2020 Census,[6] together with the official estimates as of mid-2023.[7] The table also includes the locations of the district administrative centers, the number of administrative villages in each district (128 rural desa and 6 urban kelurahan), and its postcode.
| Kode Wilayah | Name of District (kecamatan) | Area in km2 | Pop'n Census 2010 | Pop'n Census 2020 | Pop'n Estimate mid 2023 | Admin centre | No. of villages | Post code | |
|---|---|---|---|---|---|---|---|---|---|
| 12.17.06 | Sianjur Mula Mula (a) | 140.24 | 9,138 | 10,003 | 10,285 | Ginolat | 12 | 22396 | |
| 12.17.05 | Harian | 560.45 | 7,860 | 9,397 | 9,682 | Harian Boho | 13 | 22391 | |
| 12.17.09 | Sitio-tio | 50.76 | 7,124 | 8,172 | 8,378 | Sabulan | 8 | 22397 | |
| 12.17.02 | Onan Runggu | 60.89 | 10,329 | 11,122 | 11,415 | Onan Runggu | 12 | 22398 | |
| 12.17.03 | Nainggolan | 87.86 | 11,849 | 12,871 | 13,293 | Nainggolan | 15 (b) | 22394 | |
| 12.17.04 | Palipi | 129.55 | 16,087 | 18,209 | 18,849 | Mogang | 17 | 22393 | |
| 12.17.07 | Ronggur Nihuta | 94.87 | 8,356 | 9,692 | 9,960 | Ronggur Nihuta | 8 | 22392 | |
| 12.17.08 | 121.45 | 29,412 | 34,209 | 35,692 | Pasar Pangururan | 28 (c) | 22390 | ||
| 12.17.01 | Simanindo (d) | 198.20 | 19,498 | 22,766 | 23,779 | Ambarita | 21 (e) | 22395 | |
| Totals | 1,444.25 | 119,653 | 136,441 | 141,333 | Pangururan | 134 |
Notes: (a) includes the small island of Tulas (Pulau Tulas) in Lake Toba. (b) including the 2 kelurahan of Parhusip III and Siruma Hombar. (c) including the 3 kelurahan of Pasar Pangururan, Pintu Sona and Siogung Ogung. (d) includes the small islands of Pulau Tolping, Pulau Malau Satu, and Pulau Malau Dua in Lake Toba. (e) including the kelurahan of Tuktuk Siadong.
Six of the nine districts (kecamatan) within the regency are on the island of Samosir (which lies within Lake Toba), while the others lie on the 'mainland' of Sumatra.
However, a small part of Pangururan District (the two villages of Desa Tanjung Bunga and kelurahan Siogung Ogung, with a combined area of 10.50 km2 and a population of 3,222 at the 2020 Census[8]) lies on the 'mainland', cut off from the rest of the district by the canal.
2011: Samosir Regency with supervision from LIPI will build a 100-hectare Botanical Garden. It will finish 10 years later with a cost predicted about Rp.73 billion ($8.6 million).[9]
A geopark worth Rp20 billion ($2.2 million) is expected to be created - beginning in mid-2012 - in cooperation with the Agency for the Assessment and Application of Technology (BPPT). It has been proposed for incorporation into the world geopark network.[10]