Mahakam Ulu Regency (, lit. 'Upper Mahakam') is a regency (kabupaten) in the province of East Kalimantan, Indonesia. As the name implies, it comprises the upper valley of the Mahakam River. It covers a land area of 15,314.8 km2. The regency was established on 14 December 2012, formed from the former northern districts of West Kutai Regency.DPR Sahkan 7 Kabupaten Baru. www.kompas.com. Sabtu, 15 December 2012. Accessed 30 December 2012 The districts now forming the regency held a combined population of 24,994 at the 2010 Census;Biro Pusat Statistik, Jakarta, 2011. the population for the new regency at the 2020 Census was 32,513;Badan Pusat Statistik, Jakarta, 2021. the official estimate as at mid 2025 was 39,962 (comprising 21,328 males and 18,634 females).Badan Pusat Statistik, Jakarta, 27 February 2026, Kabupaten Mahakam Ulu Dalam Angka 2026 (Katalog-BPS 1102001.6411) The administrative capital is at Ujoh Bilang, which had 5,474 inhabitants as at mid 2024.Badan Pusat Statistik, Kecamatan Long Bagun 26 September 2025, Katalog-BPS 1102001.6411030.
Mahakam Ulu shares borders with Kapuas Hulu (West Kalimantan) to the west; Murung Raya, North Barito (Central Kalimantan), and West Kutai to the south, Kutai Kartanegara to the east, and Malinau to the north. It is also the only regency in East Kalimantan to share an international land border with the Malaysian state of Sarawak (Kapit), to the north. Mahakam Ulu is also notorious for being geographically isolated from the rest of East Kalimantan. As a result, the public services and transportation access are still minimal.
Administrative districts
The regency is divided into five 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 Mahakam Ulu Dalam Angka 2026 (Katalog-BPS 1102001.6411)
Notable settlements include the twin villages of Tiong Ohang and Tiong Bu'u in Long Apari District. The table also includes the locations of the district administrative centres, the number of administrative villages (all classed as kampung or desa) in each district, and its post code.
Kode Wilayah Name ofDistrict(kecamatan) Area in km2 Pop'nCensus2010 Pop'nCensus2020 Pop'nEstimatemid 2025AdmincentreNo.ofvillagesPostcode 64.11.03 Laham 901.82,2752,7493,289Laham575779 64.11.02 Long Hubung 530.96,4058,6049,412Long Hubung1175770 64.11.01 Long Bagun 4,971.27,88614,46217,017Ujoh Bilang1175767 64.11.05 Long Pahangai 3,420.24,3264,9785,406Long Pahangai1375768 64.11.04 Long Apari5,490.74,1024,2174,748Long Ohang1075769 Totals 15,314.824,99435,01039,962Ujoh Bilang50
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