National Primary Route 3

Opened : 1992 - 2010

Status : Complete

M3 Motorway Logo


Motorway : 48 km
HQDC : 5.5 km
D2AP : 12.6 km
SC : 50 km (including Donegal section)

By far the most controversial road project ever built in the State, the M3 replaces the N3 route which links Dublin with Navan and the northwest of the country. In ancient times, this road lead to Tara, seat of the high kings of Ireland. Archeological evidence in has been uncovered that suggests that the route was paved with wooden logs coveredwith gravel, after remains were discovered in a bog. The N3 still runs past the Hill of Tara today, a major part of the country's heritage.

The N3 is unusual in that it is a single-digit national route but doesn't connect Dublin with any major destination of significance at its far end, a distinction it shares only with the N5, which goes from Dublin to the small west coast town of Westport. The N3 runs northwest out of Dublin and passes through a limited number of towns. The only ones of note are Dunshaughlin, Navan, Kells, Virginia, and Belturbet. The road then crosses the border into Northern Ireland where it becomes the A509 and the A46 after it passes through County Fermanagh's main town of Enniskillen. The route runs alongside the wonderful Upper and Lower Lough Erne, a large pair of lakes that bisect the county, before passing back over the border into the Republic for the final few kilometres to Ballyshannon and the coast. From here motorists can either turn left for Sligo and the south or north for the towns of Donegal.

With the Hill of Tara and the surrounding archaeologically rich area at its centre, upgrading the N3 to the M3 would always be difficult without causing significant disruption. This was exacerbated by the Government's choice to build the new route as a tolled motorway, with two collection points. This would surely make it an expensive choice for a potential car commuter.

The new route runs parallel to the old with the exception of the Navan-Kells run, where it skirts along the western side of the towns. Travelling north from Dublin, the route runs to the west of the existing N3 before switching over to the east for the run through the Tara and Skryne valley, the gap between the Hill of Tara and the Hill of Skryne. At the far end of the valley, it switches back over to the other side again. This is the section that is most contentious, and indeed during construction the remains of a large megalithic structure were found at Lismullen.

On the other hand, the M3 is a necessary high-capacity road in order to provide county Meath with a level of road infrastructure appropriate to a region so close to a major city. The existing infrastructure is shambolic. Indeed, a railway is certainly needed also. But whether the choice to run the road through the Tara valley and risk irreparably damaging Ireland's fragile past was a worthwhile one, only time will tell.

Update 12/07/2019: N3 Jct 1-4 M50 to Clonee Widening is at Design stage. The Dunshaughlin Motorway Service Area is planned but there has been no update since 2017. Virginia Bypass is in Feasibility Study.

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Wikipedia page on this road

Pictures of this road, Videos of this road : Northern part of M3, Southern part of M3

Traffic Counts for this road


Origin M50 Junction 6, Castleknock, Dublin
Terminates Ballyshannon, Co. Donegal; including section in Northern Ireland (as A509)
Places Served Blanchardstown, Dunshaughlin, Navan, Kells
Routes Spawned -
Intersects M45 (Proposed Leinster Outer Orbital Road), M50, N52, N53


Section km Opening Date Standard
Jct 1-4 M50-Clonee (S Section) 5.5 1992-11-02 HQDC
Jct 4 M50-Clonee (N Section) 2.1 1992-11-02 M (from 2009-08-28)
Jct 4-5 Clonee/North of Kells (Part 1) 3 2010-06-04 M (from 2009-08-28)
Jct 5-10 Clonee/North of Kells (Part 2) 43 2010-06-04 M
Clonee/North of Kells (Part 3) 12.6 2010-06-04 D2AP
Belturbet Bypass 6.7 2013-12-13 SC
Jct 3 Mulhuddart Upgrade 0 2013-10-07 INTERCHANGE
Dunshaughlin Motorway Service Area MSA
M50-Clonee Jct 1-4 Widening and Upgrade (5.6) M/WIDENING
Virginia BP ? ?