The Poltross Burn is a tributary of the River Irthing. The burn rises on Denton Fell and flows north-east, joining the Irthing at Gilsland. The well preserved Roman Milecastle 48, known locally as The King's Stables, stands on the west bank. A 19th-century watermill within the village used the burn as a source of power to grind corn.
Coordinates: 54°59′29″N 2°34′27″W / 54.9915°N 2.5743°W