| Valdayka River | |
| Source1 Location: | Lake Uzhin |
| Mouth: | Lake Piros |
| Mouth Coordinates: | 58.1456°N 33.8333°W |
| Progression: | Lake Piros→ Berezayka→ |
| Subdivision Type1: | Country |
| Length: | 50km (30miles)[1] |
| Basin Size: | 783km2 |
The Valdayka (Russian: Валда́йка) is a river in Valdaysky District of Novgorod Oblast and in Bologovsky District of Tver Oblast in Russia. It is a tributary of Lake Piros and belongs to the basin of the river Msta. It is 50km (30miles) long, and the area of its basin 783km2.
The Valdayka flows over the Valdai Hills and is a part of the waterway from Lake Valdayskoye to Lake Ilmen. The source of the Valdayka is in Lake Uzhin, close to the town of Valday. The river flows north-east to Lake Piros. It runs through a number of lakes 3kmto4kmkm (02milesto02mileskm) long and 300mto400mm (1,000feetto1,300feetm) wide, in particular, Lake Zakidovskoye and Lake Plotichno. The Moscow – Saint Petersburg Railway crosses the Valdayka close to the village of Lykoshino. Since the Berezayka flows through the Lake Piros, the Valdayka is considered its tributary.
As many rivers in the Valdai Hills, it is a popular rafting route.