Black Bridge is a vehicle bridge over the Laoigh about 1½-miles upstream from the confluence of the Laoigh with the Dé.
Before Black Bridge was built - the usual route between Gleann Dhé, and upper Gleann Laoigh was the estate road from Cladh Bhòcaidh across the hill-side ; dropping into Gleann Laoigh a little downstream from where the bridge was eventually built.
In 1861 this route was described in Crombie (1861) with no reference to a bridge.
By 1866 when the area had been surveyed by the Ordnance Survey, a footbridge had been built over the Laoigh, and is shown on the old 6-inch map (1869). By implication the bridge must have been built in the early 1860s.
By 1914 Black Bridge may have been a vehicle bridge capable of supporting the weight of a car - in Gordon (1914) - the author writes :
Leaving Braemar early in the morning, we have a delightful drive up Glen Lui, but tyre troubles bring our car to a standstill, and a good deal of valuable time is lost
- Gordon (1914) (p24)
From that passage it is impossible to tell if the drive 'up Glen Lui' actually included crossing the Laoigh by Black Bridge - being considered the 'public route' it is the most likely.
By 1947 the Black Bridge I remember from my first crossings of it in the 1960s was built.