It was created in 1879 by the engineer James Leslie (1801–1889)[2] and is the oldest of the reservoirs built in the catchment of the River South Esk.

It was constructed to supply Edinburgh with water, the older and smaller reservoirs in the Pentland Hills being unable to meet the city's needs.

[4] It is a sizeable, rather shallow waterbody which contains two small islands, lying at an altitude of 270 metres (890 ft) above sea level at the foot of the Moorfoot Hills.

[5] The dam and its associated construction were built using pink sandstone and were designed to have a capacity of up to "1700 million gallons" of water.

[3] Gladhouse Reservoir is stocked with brown trout and is a popular site for fishing.