Syas

Syas
Physical characteristics
Mouth	Lake Ladoga
Length	260 km

The Syas River (Russian: Сясь) is a river in the Lyubytinsky District of Novgorod and Tikhvinsky and Volkhovsky Districts of Leningrad Oblasts, Russia. The Syas River flows from Valdai Hills north into Lake Ladoga. A town of Syasstroy is located at its mouth. It is 260 kilometres (160 mi) long, and the area of its basin 7,330 square kilometres (2,830 sq mi). The largest tributary of the Syas is the Tikhvinka River (right).

The Syas freezes up in November (sometimes in December or even January) and stays under the ice until April.

During the late Vendel Age and early Viking Age, the Syas River was popular as an alternative route to the Volkhov for penetrating from the Baltic Sea through portages to the Volga River. A fortress of Alaborg was built by the Vikings to guard the approaches to the Syas rapids. The route had declined by the 10th century.