East Kotawaringin Regency

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 15,541.75 km2, and its population was 374,175 at the 2010 Census, and 428,900 at the 2020 Census; the official estimate as at mid 2024 was 448,180 (comprising 231,400 males and 216,780 females). The town of Sampit is the capital of East Kotawaringin Regency.