The Tvertsa (Russian: Тверца́) is a river in Vyshnevolotsky, Spirovsky, Torzhoksky, and Kalininsky Districts, as well as in the cities of Torzhok and Tver in Tver Oblast, Russia, a left tributary of the Volga. It is 188 kilometres (117 mi) long, and the area of its basin 6,510 square kilometres (2,510 sq mi).