The Winster is about 20 km or 12 miles long, and rises about 2 km south of Bowness-on-Windermere, between the hamlets of Winster and Storrs (the latter is on Windermere) and follows a southerly course, flowing past the settlements of Ludderburn, Hartbarrow and Bowland Bridge, before it is joined by Arndale Beck at Bridge House.
From there, the river continues through a valley between Whitbarrow and Cartmel Fell, flowing through Helton Tarn.
It continues between the villages of Lindale and Meathop, and finally flows into the Kent estuary just downstream from Arnside.
A former course of the river joined the Kent at Blawith Point, and as a result the peninsula of Holme Island often changed hands between Lancashire and Westmorland.
Grade II listed[4]) is on a tributary of the River Winster at 54°20′27″N 2°54′18″W / 54.3408°N 2.9051°W / 54.3408; -2.9051, adjacent to A5074 road.