Yakutsk (Russian: Якутск; Yakut: Дьокуускай, romanized: J̌okuuskay, pronounced [ɟokuːskaj]) is the capital city of Sakha, Russia, located about 450 km (280 mi) south of the Arctic Circle. Fueled by the mining industry, Yakutsk has become one of Russia's most rapidly growing regional cities, with a population of 355,443 at the 2021 Census.

Yakutsk — where the average annual temperature is −8.0 °C (17.6 °F), winter high temperatures are consistently well below −20 °C (−4 °F), and the record low is −64.4 °C (−83.9 °F), — is the coldest city in the world. Yakutsk is also the largest city located in continuous permafrost; the only other large city is Norilsk, also in Siberia. Yakutsk is located in the Central Yakutian Lowland and is a major port on the Lena River. It is served by the Yakutsk Airport as well as the smaller Magan Airport.