A waterfall immediately west of the bridge, renowned as a beauty spot from at least the 18th century, was lost with the construction of the Poulaphouca Reservoir.

The waterfall, marked as 'Poolapooka - a remarkable cataract' on Noble & Keenan's map of 1752,[3] is depicted and described in the Post-Chaise Companion of 1786, when Ballymore parish was still within Dublin: Poll-A-Phuca or the Daemon's Hole, being a grand waterfall formed from the head of the Liffey, that rises from the Wicklow Mountains, and here divides the counties of Wicklow and Dublin.

[5][6][7][8][9][10] Wright's Guide to the County of Wicklow describes the bridge and waterfall in 1827:The celebrated fall of the River Liffey, called Pol-a-Phuca or the Daemon's Hole, is about one mile from the village of Ballymore Eustace.

The chasm through which the water rushes is only forty feet wide, lined on each side with perpendicular masses of Greywacke rock.

Here the whole body of water composing the stream of the Liffey, rushes down with the utmost impetuosity into a circular basin of stone, worn perfectly smooth, the form of which imparts to the water a rotatory motion...across this chasm a bridge has been thrown, to continue the new line of road to New Ross, the span of the arch is 65 feet, the altitude of the chord above the upper fall is 47, and the height of the keystone of the arch above the river's bed 150 feet; from the battlements there is a direct perpendicular view into the whirlpool just now described, and which gives name to the waterfall.