White Bridge is the, mostly, wooden vehicle bridge over Uisge Dé a short distance upstream from the confluence of Uisge Gheallaidh with Uisge Dé.
As a place name there's little reason to believe that the derivation of White Bridge isn't literal, and English - there are references to it being painted white. There's also a possibility that the name is derived from the mis-Anglicisation of Gheallaidh to give ''White Dee'', suggesting the possibility that the White Bridge name is a reference to the glen one approaches by crossing the bridge from Gleann Dhé.
By 1866 when the area was surveyed by the Ordnance Survey, a bridge had already been built over Uisge Dé at the same point as the current bridge. The bridge, as it's shown on the old 6-inch map (1869) appears to be wide enough for a horse drawn vehicle. In McConnochie (1898) the author apparently refers to this bridge - writing :
White Bridge, the uppermost bridge over the Dee - we do not take into account the occasional plank and stilts which do duty at Corrour! - crosses the river a few yards above its confluence with the Geldie, at a point which has been well described as ''beautifully desolate". The bridge is built of timber with stone piers, succeeding a foot-bridge with a ford a little lower down
- McConnochie (1898) (p13-14)
As seems likely, if the vehicle bridge was built before the Ordnance Survey of 1866, I'd be very interested in knowing more about the footbridge, and when it was replaced by the vehicle bridge.
It's certain that the bridge was painted white at some point ; if it was painted when it was built it's odd that there's no reference to it being white McConnochie (1898).
In 1917 the earliest contemporary reference I’ve seen to the bridge ever being white was published in the Cairngorm Club Journal. In the article Beinn A' Ghlo from Braemar by (I assume) Robert Anderson, Editor (ccj 48, July 1917, p245-250) describing a 'tramp' in July 1916 – the author writes :
After crossing the White Bridge (now no longer white) ...
- Robert Anderson (ccj 48, July 1917, p245)
Evidently the bridge was painted white within the memory of the author ; and the fact that it no longer was is significant enough for the author to point that out. Apparently the bridge was repainted - in Alexander (1928) the author refers to it being painted white - writing :
The White Bridge, a substantial wooden structure, painted white, is a well-known landmark in the Cairngorms
- Alexander (1928) (p57)
I'm hoping that one day I'll get my hands on old photographs of the White Bridge taken when it really was white, not just a weathered silvery-gray.