The lake is 1.6 km (1 mi) long and approximately 100 m (328 ft) wide at its maximum breadth.

The Fonthill Brook flows out of the southern end of the lake and joins the River Nadder at Tisbury, 2 km (1 mi) to the southeast.

[1] The lake was created in the mid-18th century by building a weir below fish-ponds fed by the brook, for Alderman William Beckford, the builder of the house later known as Fonthill Splendens.

[2] A sizeable population of the introduced Mandarin duck is resident at Fonthill Lake (and on surrounding rivers) together with a number of wild swans.

[3] It is also where the ashes of pioneering Everest mountaineer Eric Shipton were scattered.