| Severnaya Sosva | |
| Other Name: | Северная Сосьва |
| Subdivision Type1: | Country |
| Subdivision Name1: | Russia |
| Subdivision Type3: | Region |
| Subdivision Name3: | Khanty-Mansi Autonomous Okrug |
| Subdivision Type5: | City |
| Subdivision Name5: | Berezovo |
| Length: | 754km (469miles) |
| Discharge1 Avg: | 860m3/s |
| Mouth: | Malaya Ob |
| Mouth Coordinates: | 64.1897°N 65.4319°W |
| Progression: | Malaya Ob→ |
| Basin Size: | 98300km2 |
| Tributaries Left: | Lyapin, Vogulka |
| Tributaries Right: | Malaya Sosva, Tapsuy |
| Pushpin Map: | Russia Khanty-Mansi Autonomous Okrug |
| Pushpin Map Caption: | Mouth location in Khanty-Mansi Autonomous Okrug, Russia |
The Severnaya Sosva (Russian: Северная Сосьва, "Northern Sosva”; Mansi: Та̄гт-я̄, Tāgt-jā) is a river in Khanty-Mansi Autonomous Okrug, Russia, which drains the northern Ural Mountains into the lower Ob. It discharges into the Malaya Ob, a branch of the Ob.[1]
The river and its tributaries are basically T-shaped. The Khulga and Lyapin flow south for about 125miles parallel to the Urals while the main Northern Sosva flows about 125miles northward. The united rivers then flow east southeast about 100miles almost to the Ob near Igrim and then flow north about 50miles before joining the Ob at Beryozovo. Its headwaters are just east of the headwaters of the Pechora on the other side of the Urals and somewhat north of the headwaters of the southeast-flowing Pelym.
The Severnaya Sosva is 754km (469miles) long, and the area of its basin is 98300km2. The average discharge of the river is 860m3/s.[1] It is frozen between November and April and floods (mostly snowmelt) from May to September. Like many rivers in the West Siberian Plain, it has an extensive flood plain with marshes and meanders. In spring the area near the Ob often floods. The channel width sometimes approaches 1km (01miles) and the flood plain 40km (30miles). The river is navigable by ships in the lower region.
There are two Malaya Sosva rivers. The larger flows north to join the Northern Sosva near Igrim. The other joins the Bolshaya Sosva to form the Northern Sosva.
There was some ill-documented Russian trade in the area before the Russian conquest of Siberia. After about 1593 the Northern Sosva was one of the main routes into Siberia (for the others, see Verkhoturye). The route ran from the Pechora River, up the Shchugor River, over either of two passes and down the Sosva to the Ob and the fur-rich Mangazeya region. By the late 17th century the fur trade declined and most trade shifted south to Verkhoturye and some north to the Usa.