From the Wikipedia page 
Kotlassky District (Russian: Ко́тласский райо́н) is an administrative district (raion), one of the twenty-one in Arkhangelsk Oblast, Russia. As a municipal division, it is incorporated as Kotlassky Municipal District. It is located in the southeast of the oblast and borders with Krasnoborsky District in the north, Lensky District in the northeast, Vilegodsky District in the east, Luzsky District of Kirov Oblast and Velikoustyugsky District of Vologda Oblast in the south, and with Ustyansky District in the west. The area of the district is 6,300 square kilometers (2,400 sq mi). Its administrative center is the town of Kotlas (which is not administratively a part of the district).