Kalininsky District
The drainage basin of the Tvertsa includes the southwestern part of Vyshnevolotsky District, the western parts of Spirovsky and Likhoslavlsky Districts, the major part of Torzhoksky District, the eastern part of Kuvshinovsky District, and the northwestern part of Kalininsky District, all of Tver Oblast, as well as the town of Torzhok and parts of the cities of Vyshny Volochyok and Tver.