Irish Roads

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Primary Roads
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Roads in Detail
The North
Items of Note

N1 M1

Details of the N1 national primary road.

Map of current national primary routes
Works ongoing along the M1 Santry Bypass
on the M50 Dublin Port Tunnel in 2004.
Photo Sean McClean, licenced under GFDL.

Terminal Destinations:

Dublin -> Belfast [1]


The N1 is 97.1 km long, and runs from Dublin city centre north to the border with Northern Ireland. From the Santry Bypass to north of Dundalk, the route is the M1 motorway. The M1 bypasses Swords, Drogheda and Dundalk.

Route description:

The N1 begins in Dublin City at Bachelor's Walk where it connects to the N4. From here it follows O'Connell Bridge, O'Connell Street, Parnell Street, Parnell Square West, Granby Row, Dorset Street Upper (and via North Frederick Street, Parnell Square East and Cavendish Row), Dorset Street Lower, Drumcondra Road and the Swords Road. From here, the M1 motorway commences as the Santry Bypass, and continues the N1 route to north of Dundalk. North of Dundalk the route continues as standard two lane to the border, although an upgrade/bypass of motorway/dual carriageway standard is under way. Across the border the route becomes the A1; with traffic to Belfast joining Northern Ireland's M1 further north near Lisburn.

M1 motorway:

The M1 motorway is that part of the N1 that is of motorway standard. The M1 commences as the Santry Bypass; the M50 Dublin Port Tunnel will join the M1 along this first section. At Turnapin the M50 Dublin Ring Road meets the M1 at a grade separated roundabout junction (with the roundabout at-grade for the M50). Dublin Airport is served by a junction and spur north of this. The M1 continues through north County Dublin, bypassing Balbriggan to the west. After passing through County Meath for 14.3 km the route crosses into County Louth, crossing the River Boyne west of Drogheda on a cable-stayed bridge. The M1 passes west of Dunleer and Dundalk as it continues through County Louth. North of Dundalk the motorway ends as of October 2006.

The M1 was constructed in several stages. The first section to open, in the mid-1980s, was between Whitehall and Dublin Airport. Nearly a decade later in 1993, the next section, the 6.5 km Dunleer bypass opened in County Louth, running west of Dunleer. The 13km Balbriggan bypass, located mostly in north Co. Dublin and west of Balbriggan, followed in 1998. At this stage the various M1 motorway sections were connected only by standard carriageway sections of the N1. The next M1 project however was a 16 km link in County Louth between Dunleer and Dundalk, this scheme, which opened in 2001, continued directly north from the M1 Dunleer Bypass.

2003 was the big year for the M1 motorway. The missing section between the Dublin Airport junction and the Balbriggan bypass was built as two separate projects; Cloghran-Lissenhall (6.5 km) and Lissenhall-Balbriggan (9.9 km); both opened in 2003. The section between the end of the Balbriggan Bypass and the start of the Dunleer Bypass was completed by the 21.5 km Drogheda Bypass that opened in the same year. Dundalk was bypassed in 2005 by a 11 km section of M1 motorway passing west and around the north of the town.

Upgrade plans:

The section of N1 from north of Dundalk to the border is standard two lane as of October 2006. This will be replaced by a 9.4 km section of motorway and dual carriageway, under construction and due to open in late 2007. The A1 route north of the border to Newry is also being replaced by dual carriageway (4.6 km) as part of the same scheme, the first such cross-border project.


[1] Traffic Signs Manual, Chapter 2, Appendix 2, Table A2.2 - Terminal Destinations for National Routes : National Primary Routes, Dept. of Environment, 1994.


S.I. No. 187 of 2006 - Roads Act 1993 (Classification of National Roads) Order 2006 [PDF - 353 kB], Dept. of Transport website, accessed 25 Oct 2006.

National Route Lengths as of 31/12/2005 [PDF - 641 kB], NRA website, accessed 25 Oct 2006.

National Roads Authority Annual Report 2004 and Programme for 2005 [PDF - 1.4 MB], page 89, Appendix 2. NRA website, accessed 25 Oct 2006.


Map of M1/N1: Dundalk to the Border [PDF - 536 kB], NRA website, accessed 25 Oct 2006.

National Roads Authority: N1/M1 Dundalk Western Bypass, NRA website, accessed 25 Oct 2006.

Map of M1 Dundalk Western Bypass [PDF - 347 kB], NRA website, accessed 25 Oct 2006.

M1 Dundalk Western Bypass Official Opening Brochure [PDF - 2.1 MB], NRA website, accessed 25 Oct 2006.

National Roads Authority: Downloadable Documentation (M1 Drogheda Bypass), NRA website, accessed 25 Oct 2006.

Map of M1 Drogheda Bypass [PDF - 2.4 MB], NRA website, accessed 25 Oct 2006.

Copyright 2006 Conal Watterson
(except where otherwise noted).

Last updated: 25 October 2006.