| Sviyaga | |
| Mouth Coordinates: | 55.7311°N 48.6158°W |
| Subdivision Type1: | Country |
| Length: | 375km (233miles) |
| Source1 Elevation: | 100m (300feet) |
| Mouth Elevation: | 53m (174feet) |
| Discharge1 Avg: | 1590m3/s (near mouth) |
| Basin Size: | 16700km2 |
The Sviyaga (; Tatar: Зөя;, Sĕve) is a river in the Ulyanovsk Oblast and Tatarstan, a right tributary of the Volga.[1] It is 375km (233miles) long, and its drainage basin covers 16700km2.[2] The Sviyaga flows into the Sviyaga Cove of the Kuybyshev Reservoir, west of Kazan. It freezes up in November or December and stays under the ice until April or May. Major tributaries are the Arya, Birlya, Bula, Karla, Kubnya, Sulitsa and Tosha rivers.
The city of Ulyanovsk is along the Sviyaga. In Ulyanovsk, the Sviyaga flows only a few kilometres away from the Volga, but their confluence is about 200km (100miles) north of Ulyanovsk.
The castle of Sviyazhsk, which dates to 1551, is on the island in Sviyaga Cove of the Kuybyshev Reservoir.