Here’s an excerpt from The Dublin Builder (Vol. VII, No. 138, p. 228, September 15, 1865)*:

New Bridge at Enniskerry

A handsome singe-span bridge, dressed with cut granite, is in the course of erection of the river at Enniskerry, county Wicklow, from designs by Mr H. Brett, county surveyor. When completed it will be broad and level, and will present handsome balustrades, and add increased picturesqueness to this already favoured locality. It is contemplated to erect a hotel close to, and on the Dublin side of this bridge, in an elevated position, commanding a fine prospect of the Enniskerry vale and its surrounding heights; the cost of erection to be defrayed by Viscount Powerscourt. The bridge is being erected jointly by his lordship and the grand jury of the county.

The bridge, which crosses the river at the Bog Meadow running alongside the Powerscourt Arms has a rich archival history. Immediately preceding the new bridge of 1865, there was an iron bridge, captured in one of Lewis Wingfield’s photographs of the village (I have included this picture in the book). Before this, there are several sources to show there was a three-arch bridge crossing the river. For example, in the Prints and Drawings collection at the National Library, there are several sketches by Samuel Brocas;  two of which are of the village in 1822 and include the bridge. In addition, one of these shows a mill-race to the village side of the bridge underneath what is the hotel car-park today. Samuel’s brother William also sketched the bridge, with a clearer view of the millrace. Both sketches show a small dwelling beside the bridge under where the car-park would be today, between the millrace and the main river.

*Source: National Library of Ireland.