Udomlya (Russian: Удо́мля) is a town and the administrative center of Udomelsky District in Tver Oblast, Russia, located on the shores of Lake Pesvo on the Rybinsk–Bologoye railway, 225 kilometers (140 mi) north of Tver, the administrative center of the oblast.

[12] Udomelsky District, with the administrative center in Udomlya, was established within Tver Okrug of Moscow Oblast.

[6] The main industrial enterprise in Udomlya is the Kalinin Nuclear Power Plant (98% volume of industrial production in Udomlya District, 70% of electric power produced in Tver Oblast and 2,5 % of goods and products of Tver Oblast).

Udomlya contains four objects classified as cultural and historical heritage of local significance, which are the Gudzovsky warehouse, built in 1882, a building where a Young Pioneer club was located, a monument to soldiers fallen in World War II, and a monument to Alexander Popov.

[17] The former Dacha Chayka on the shores of Lake Udomlya, located close to the town, which belonged to artist Vitold Byalynitsky-Birulya, is also open as a museum.