Kildangan Railway Bridge is to be closed for up to 12 weeks.
Kildare County Council says it is to resurfacing of roads and installation of new footpaths.
The closure will be in place between July 20th and October 9th.
Vehicles travelling northeast towards Kildangan Bridge from Crosskeys will be redirected further along the R417 (circa 4.5km) towards Monasterevin. They will then be redirected to the L7055 Nurney Road (circa 6km) to finish at Duneany Cross Roads.
Vehicles travelling southwest from Kildare will be redirected along the L7055 towards Monasterevin. They will then be redirected to the R417 (circa 5km) towards Kildangan to finish at Crosskey.
Diversionary routes will be clearly signposted, as agreed with the Council and An Garda Síochána. Emergency access and restricted local access will be maintained.
Image courtesy KCC