Hayeswater is a small lake within the Lake District
National Park and is situated about a mile (1.6 km) SE of the hamlet of
Hartsop in the Patterdale Valley.
The lake is natural but now used as a reservoir
serving the Cumbrian town of Penrith.
It is fed from the south by Hayeswater Gill, which rises close to the
route of the Roman High Street and continues to Cow Bridge where it
joins the outlet stream from Brothers Water.