Ciste Dhé is a series of swimmable pools in the Dé a short distance upstream from the White Bridge. The pools are most easily reachable from the estate road on the west bank.
As a place name Ciste Dhé - means chest of dee.
There is evidence for the existence of a footbridge over the river at Ciste Dhé about the middle of 19th century. An interesting tid-bit of information appears in Tait's (1848) - the author of an anonymous article describing the Dé, and counting the bridges over it (counting upstream from its mouth) - writes :
the tenth at Mar Lodge, erected by the Duke of Leeds, during the last autumn ... the eleventh at the Linn ; and the twelfth is the very rickety establishment over the Chest
- Tait's (1848) (p725)
From this quote - it's clear the White Bridge was not built until sometime after 1848, and the bridge at Ciste Dhé was the highest one over the Dé then.