It runs through the South of County Dublin for its entire length.

East-West: Starts at N11 Cherrywood Road and runs under the old Harcourt Street railway line viaduct and on through Brides Glen where it goes under the M50 and crosses over the Loughlinstown River.

Proceeds east along Ballycorus Road to a junction with the R117 in Kilternan.

Crosses the R117 at a staggered junction in Kilternan before climbing steeply SW up Ballybetagh Road to Glencullen.

From the head of the valley it descends steeply through the Pine Forest and continues down through Rockbrook and Edmondstown (where it again passes underneath the M50) to its termination in Ballyboden where it meets the R115.