Lensky District is an administrative district (raion), one of the twenty-one in Arkhangelsk Oblast, Russia. As a municipal division, it is incorporated as Lensky Municipal District. It is located in the southeast of the oblast and borders with Udorsky District of the Komi Republic in the north, Syktyvdinsky, Ust-Vymsky, and Sysolsky Districts, also of the Komi Republic, in the east, Vilegodsky District in the south, and with Kotlassky and Krasnoborsky Districts in the west. The area of the district is . Its administrative center is the rural locality (a selo) of Yarensk. Population: The population of Yarensk accounts for 27.4% of the district's total population.