The car ferry is located in the North East of the city in the docks. As Orlagh House is located in the South West of Dublin, one can either cut though the city centre via Terenure in the most direct route (45 mins, 16km) or go directly left from Dublin Port, and continue West to meet the M50 (36 mins, 23km)

Directions and map may also be found at AA Route Planner

Take the M1 South signposted Dublin.
Before Sprucefield, take the A1 Southbound past Hillsborough Castle and Gardens.
Follow A1 for some 50km which crosses border and becomes N1 and then M1, for further 80km.
Continue until Junction 1 (which joins the M50), and then proceed southbound.
After 20 minutes, exit at junction 12 of the M50 (which is signposted to Firhouse/R113).
Take a right onto Scholarstown Road and proceed to the first set of traffic lights.
Take a left at these traffic lights, and then go straight through two roundabouts.
Continue straight for a couple of hundred yards, and the gates to Orlagh House will be directly in front of you.
Go through the gates and follow the private roadway up to the house.

Directions and map may also be viewed at AA Route Planner

Possibly the easiest was to get to Orlagh House is by LUAS, Dublin’s tram system. Trams are very frequent and well signposted.

Take the LUAS Red line from anywhere in the city centre, to the terminus at Tallaght.
Disembark and get a taxi, which will take a further 10 mins to get to Orlagh House.
The postcode is D16 VF38 and make sure the taxi goes past the gate and all the way to the house, as otherwise you have a long walk up the driveway!

You can see the full Luas Red Line list of stops here.

The 15 and 15b busses run 24-hours-a-day into the city centre.