Bontang is a city on the eastern coast of the island of Borneo in Indonesia, in the province of East Kalimantan. It occupies an area of 161.88 km2 (62.50 sq mi), and the population was 140,787 at the 2010 census, and 178,917 at the 2020 census. It is also the third most densely populated place in the province after Balikpapan and Samarinda.