Smiddyhill Bridge carries the B6355 across the Whiteadder Water at the southern side of the scattered community of Cranshaws. It is a narrow twin arch stone bridge with the central pier founded in the riverbed, but the western arch normally only crosses the riverbank, acting as a flood arch when the river is in spate. The bridge is unusually neatly detailed for its relatively remote location, with ashlar arch rings, projecting string course and coping stones on the parapets. The rest of the stonework is generally grey rubble, but there is variation in the colours. Square piers rise up the abutments, with quoins on the corners, beyond which the wing walls flare out. The central pier between the arches is protected by a bullnosed cutwater, contrasting with the sharp lines of the rest of the structure.
The roadway over the bridge is a single lane wide, but there is good visibility from either bank to allow traffic to hold back if another vehicle is already crossing. As the bridge spans the river at right angles, while the road is following the valley, the road has to turn quite tightly on either bank. This is amply accommodated with the spayed wing walls.
