Yakutsk is the capital city of the Sakha Republic, Russia, located about 450 kilometers (280 mi) south of the Arctic Circle. Population: 269,601. Yakutsk is a major port on the Lena River. It is served by the Yakutsk Airport as well as the smaller Magan Airport. It is a major supplier of diamonds. Its average winter temperature is −34 °C (−30 °F), which makes Yakutsk the coldest major city in the world.