| Southwest Aceh Regency | |
| Native Name: | Kabupaten Aceh Barat Daya |
| Native Name Lang: | id |
| Settlement Type: | Regency |
| Motto: | Sapeu Kheun Sahoe Langkah (Same Word Same Step) |
| Coordinates: | 3.7911°N 96.9166°W |
| Subdivision Type: | Country |
| Subdivision Name: |  Indonesia |
| Subdivision Type1: | Region |
| Subdivision Name1: | Sumatra |
| Subdivision Type2: | Province |
| Established Title: | Established |
| Established Date: | 2002 |
| Seat Type: | Regency seat |
| Seat: | Blangpidie |
| Leader Title: | Regent |
| Leader Name: | Darmansah |
| Leader Title1: | Vice Regent |
| Leader Name1: | Vacant |
| Unit Pref: | Metric |
| Area Total Km2: | 1882.99 |
| Population Footnotes: | [1] |
| Population Total: | 156990 |
| Population As Of: | mid 2023 estimate |
| Population Density Km2: | auto |
| Timezone1: | IWST |
| Utc Offset1: | +7 |
| Area Code Type: | Area code |
| Area Code: | (+62) 659 |
| Pushpin Map: | Indonesia_Aceh#Indonesia_Sumatra North#Indonesia_Sumatra#Indonesia |
| Pushpin Map Caption: | Location in Aceh, Northern Sumatra, Sumatra and Indonesia |
Southwest Aceh Regency (Indonesian: Kabupaten Aceh Barat Daya) is a regency in the Aceh Province of Indonesia. The regency was created on 10 April 2002 from the northwestern districts of South Aceh Regency. It is located on the west side of the island of Sumatra. The regency covers an area of 1,882.99 square kilometres and according to the 2010 census had a population of 126,036;[2] this rose to 140,366 at the 2015 Census, and to 150,775 at the 2020 Census;[3] the official estimate as at mid 2023 was 156,990.[4] The seat of the regency government is the town of Blangpidie.
The regency is divided administratively into nine districts (kecamatan), tabulated below with their areas (in km2) and their populations at the 2010 Census[5] and the 2020 Census,[6] together with the official estimates as at mid 2022.[7] The table also includes the locations of the district administrative centres, the number of villages (gampong) in each district, and its postal codes.
| Kode Wilayah | Name of District (kecamatan) | Area in km2 | Pop'n Census 2010 | Pop'n Census 2020 | Pop'n Estimate mid 2022 | Admin centre | No. of villages | Post codes | |
|---|---|---|---|---|---|---|---|---|---|
| 11.12.03 | 100.68 | 12,670 | 15,331 | 15,799 | Kedai Manggeng | 18 | 23760 | ||
| 11.12.09 | 110.23 | 9,771 | 11,121 | 11,325 | Cot Bak U | 14 | 23762 | ||
| 11.12.02 | 63.60 | 11,509 | 13,704 | 14,078 | Tanjung Bunga | 15 | 23768 | ||
| 11.12.07 | 30.21 | 7,461 | 8,673 | 8,869 | Lhang | 9 | 23763 | ||
| 11.12.01 | 486.95 | 20,084 | 23,810 | 24,440 | Pasar Blangpidie | 20 | 23764 | ||
| 11.12.08 | 225.78 | 9,481 | 11,338 | 11,657 | Alue Sungai Pinang | 12 | 23769 | ||
| 11.12.04 | 18.71 | 20,901 | 24,619 | 25,238 | Padang Baru | 29 | 23765 | ||
| 11.12.05 | 287.32 | 17,740 | 21,383 | 22,019 | Pasar Kota Bahagia | 21 | 23766 | ||
| 11.12.06 | 559.52 | 16,419 | 20,796 | 21,621 | Pante Rakyat | 14 | 23767 | ||
| Totals | 1,882.99 | 126,036 | 150,775 | 155,046 | Blangpidie | 152 |