Buina rises at the northernmost end of the Blue Mountains in the north of Kaedwen and meanders through the northern part of the Kestrel Mountains. It has two tributaries. Towards the west and branching south is the Gwenllech. The Nimnar branches off to the south towards Ghelibol.
The Buina forms the border between the Hengfors League and Redania flowing towards the Arc Coast and emptying into the Gulf of Praxeda on the Great Sea near Blaviken.