An old sign for the N9, when the road still went through Carlow. This sign has now been replaced.
The N9 is the main road connecting Dublin (via the N7 to Newbridge) and Waterford. Almost all of it of it, having been upgraded from High Quality Dual Carriageway to Motorway status, is now made up of the M9. The only section of the route still signed as N9 is the final half a kilometre from the end of the M9 (where it meets the N24) to the roundabout junction with the N25.
The N9 originally started at the junction of Main Street and New Row in the centre of Naas. The old road to Waterford is now the R448.
Until the opening of the Suir Bridge and Waterford Bypass in 2009, the N9 ended at the north end of the Rice Bridge on what was the N25. A short section of the N9 that bypassed the old road, south of the main bypass, is now the R861.