From A Wiki of Ice and Fire
and the location of the Westwatch-by-the-Bridge
Westwatch-by-the-Bridge is the westernmost castle of the Night's Watch. The abandoned castle is west of the Shadow Tower, on the other side of the Gorge by the Bridge of Skulls.
A Dance with Dragons
Lord Commander Jon Snow has Westwatch re-garrisoned with a small company of men from the Night's Watch.
References and Notes