Upper Tamar lake is a reservoir on the border of Cornwall and Devon in south-west England.

[1] The reservoir serves the water supply in the Bude area of Cornwall and surrounding districts, including Clovelly, Bradworthy and Warbstow.

The county boundary follows the line of the river as it was prior to the construction of the reservoir, therefore now within the lake, resulting in it being in both Devon and Cornwall.

[3] The lake was planned as an expansion of the local water supply, and to avoid a potential drought in the area.

[1] The Upper Tamar Sailing Club (UTLSC) is a group of regular sailors on the lake.