Lensky District (Russian: Ле́нский улу́с; Yakut: Ленскэй улууһа, Lyenskey uluuha) is an administrative and municipal district (raion, or ulus), one of the thirty-four in the Sakha Republic, Russia. It is located in the southwest of the republic and borders with Mirninsky District in the north, Suntarsky District in the northeast, Olyokminsky District in the east, and with Irkutsk Oblast in the south and west. The area of the district is 77,000 square kilometers (30,000 sq mi). Its administrative center is the town of Lensk. Population: 39,765 (2010 Census); 38,669 (2002 Census); 49,702 (1989 Census). The population of Lensk accounts for 62.8% of the district's total population.