East Kotawaringin Regency (Indonesian: Kabupaten Kotawaringin Timur) is one of the thirteen regencies which comprise the Central Kalimantan Province on the island of Kalimantan (Borneo), Indonesia. It originally covered a much larger part of the province, having been split from a single Kotawaringin Regency on 26 June 1959 into separate regencies for East and West Kotawaringin, but on 10 April 2002 several districts in the west of the regency were split off to form the new Seruyan Regency, and several districts in the east of the regency were similarly split off to form the new Katingan Regency. The area of the residual East Kotawaringin Regency is 16,796 km, and its population was 374,175 at the 2010 Census, and 428,900 at the 2020 Census; the official estimate as at mid 2023 was 443,359 (comprising 229,220 males and 214,139 females). The town of Sampit is the capital of East Kotawaringin Regency.

At the 2010 Census, East Kotawaringin Regency consisted of fifteen districts (kecamatan), but two more districts (Tualan Hulu and Telaga Antang) were subsequently established by the splitting of existing districts. The seventeen districts are tabulated below with their areas and population totals from the 2010 Census and the 2020 Census, together with the official estimates as at mid 2023. The table also includes the locations of the district administrative centres, the number of administrative villages in each district (totaling 168 rural desa and 17 urban kelurahan), and its postal codes.

Kode Wilayah	Name of District (kecamatan)	Area in km	Pop'n Census 2010	Pop'n Census 2020	Pop'n Estimate mid 2023	Admin centre	No. of villages	Post codes
62.02.08	Mentaya Hilir Selatan (South Lower Mentaya)	318.00	20,801	23,010	23,163	Samuda	10	74363
62.02.11	Teluk Sampit (Sampit Bay)	610.00	8,935	10,562	10,839	Ujung Pandaran	6	74364
62.02.09	Pulau Hanaut (Hanaut Island)	620.00	15,473	16,809	16,832	Bapinang	14	74362
62.02.06	Mentawa Baru Ketapang	726.00	76,951	98,680	103,688	Sampit	11	74321 - 76326
62.02.12	Seranau	548.00	9,587	10,874	11,026	Mentaya Seberang	6	74314 - 74315
62.02.07	Mentaya Hilir Utara (North Lower Mentaya)	725.00	15,840	18,780	19,289	Bagendang	7	74361
62.02.01	Kota Besi	1,889.00	14,980	18,444	19,153	Kota Besi	11	74353
62.02.14	Telawang	317.00	16,823	20,518	21,248	Sebabi	6	74350
62.02.05	Baamang	639.00	51,538	69,714	74,397	Baamang	6	74311 - 74316
62.02.02	Cempaga	1,253.00	19,076	22,297	22,807	Cempaga Mulia	8	74354
62.02.13	Cempaga Hulu (Upper Cempaga)	1,183.00	23,262	21,586	21,871	Pundu	11	74359
62.02.04	Parenggean	493.15	35,608	26,628	26,819	Parenggean	15	74355
62.02.16	Tualan Hulu (Upper Tualan)	1,095.85		7,766	7,868	Luwuk Sampun	11	74358
62.02.03	Mentaya Hulu (Upper Mentaya)	1,712.79	28,522	20,533	20,804	Kuala Kuayan	16	74357
62.02.15	Bukit Santuai	1,636.00	8,038	10,380	10,929	Tumbang Penyahuan	14	74356
62.02.10	Antang Kalang	1,579.00	28,741	13,357	13,533	Tumbang Kalang	15	74352
62.02.17	Telaga Antang (Lake Antang)	1,456.21		18,957	19,093	Tumbang Mangkup	18	74352
	Totals	16,796.00	374,175	428,895	443,359	Sampit	185

Notes: (a) comprises 2 kelurahan (Samuda Kota and Basirih Hilir) and 8 desa. (b) comprises 5 kelurahan (Ketapang, Mentawa Baru Hilir, Mentawa Baru Hulu, Pasir Putih and Sawahan) and 6 desa. (c) including one kelurahan (the district admin centre).
(d) except for the village of Mentaya Seberang, which has a post code of 74324.
(e) comprises 2 kelurahan (Kota Besi Hilir and Kota Besi Hulu) and 9 desa.
(f) comprises 5 kelurahan (Baamang Barat, Baamang Hilir, Baamang Hulu, Baamang Tengah and Tanah Mas) and 1 desa.
(g) the 2010 population of Tualan Hulu District is included in the figures for the districts from which it was cut out.
(h) the 2010 population of Telaga Antang District is included in the figure for Antang Kalang District.
(i) except for the village of Buana Mustika, which has a post code of 74356.

2°05′00″S 112°45′00″E / 2.0833°S 112.7500°E / -2.0833; 112.7500