R423 road
Bóthar R423
R423 leaving Mountrath
Route information
Length	30 km (19 mi)
Location
Country	Ireland
Primary destinations	County Offaly Near Portarlington – leave the R420; crosses the Portarlington-Athlone railway line County Laois Joins the R422 Mountmellick – leaves the R422 and joins the N80 Leaves the N80 Ballyfin Mountrath – terminates at the R440 near the R445 junction
Highway system
Roads in Ireland Motorways Primary Secondary Regional

The R423 road is a regional road in Ireland linking Portarlington, County Laois to Mountrath, County Laois. It passes through the village of Mountmellick en route. The road is 30 km (19 mi) long.