Krasnomaysky (Russian: Краснома́йский) is an urban-type settlement in Vyshnevolotsky District of Tver Oblast, Russia.

Klyuchino was located on the bank of the Shlina, close to the portage to the Tvertsa River, one of the most popular trade routed of the medieval Russia.

Subsequently, the plant was sold to merchant Andrey Bolotin, who converted it into a glass-making factory.

The factory was nationalized in 1920 and renamed Krasny May ("Red May", referring to International Workers' Day) in 1923.

[11] Krasnomaysky is located close to Leontyevo railway station on the railroad connecting Moscow and St. Petersburg.