- See also: Sellen River and East Sellen River
The West Sellen River is part of the vast Sellen River system but is, in itself, a long and important river forming the boundaries between nations for its entire 1,200-mile length.
The Worldwound and Mendev border
The West Sellen rises in the far north of Avistan and forms the border between the demon-infested Worldwound and the country set against the demon incursion: Mendev. Through this phase it flows in a south-westerly direction. While in Mendev it passes the city of Kenabres.
The Worldwound and Numeria border
Ustalav and Numeria border
The West Sellen provides the eastern national boundary of Ustalav: in the north with Numeria and, in the south, with the River Kingdoms.
The river enters Ustalav at Lake Prophyria, in county Sinaria, where its waters are increased by the entry of the Moutray River; there it turns to a more southerly flow. With the Babelwood on its western shore, it enters the county of Barstoi and is joined by its tributary, the Delgavia River, north of the settlement of Vische. North of Sturnidae the river changes course again to a more easterly flow and is joined by the Kingfisher River at the border of Barstoi with the county of Varno. Shortly after entering Varno, the river once more resumes a southerly flow and meets its tributary, the Seaugustae River. Just east of Lake Laruba the border of Numeria veers eastwards and the river now becomes the border between Ustalav and the River Kingdoms.
Ustalav and the River Kingdoms border
South of Lake Laruba, the River Kingdoms form the eastern bank of the West Sellen River. In this phase the river is joined by its tributary, the Twinetongue River. Eventually, the border of Ustalav turns westward and the river now becomes the border between Razmiran and the River Kingdoms, as the river continues southwards.
Razmiran and the River Kingdoms border
Kyonin and the River Kingdoms border
Paizo published a major article about the Sellen River, including the West Sellen River, in Dreams of the Yellow King.