The N4 road is a

national primary road A national primary road () is a road classification in Republic of Ireland, Ireland. National primary roads form the major routes between the major urban centres. There are 2649 km of national primary roads. This category of road has the pr ...

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

, running from

Dublin Dublin is the capital and largest city of Republic of Ireland, Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, and is bordered on the south by the Dublin Mountains, pa ...

to the northwest of Ireland and

Sligo Sligo ( ; , meaning 'abounding in shells') is a coastal seaport and the county town of County Sligo, Ireland, within the western province of Connacht. With a population of 20,608 in 2022, it is the county's largest urban centre (constituting 2 ...

town. The M6 to

Galway Galway ( ; , ) is a City status in Ireland, city in (and the county town of) County Galway. It lies on the River Corrib between Lough Corrib and Galway Bay. It is the most populous settlement in the province of Connacht, the List of settleme ...

diverges from this route after Kinnegad, while the N5 to Westport diverges at Longford town. Most sections of the N4 that are motorway-standard are designated the M4 motorway.

Road standard

The N4 originates at an intersection with the M50 motorway at Junction 7. This is also Junction 1 of the N/M4. The

Liffey Valley Shopping Centre Liffey Valley Shopping Centre is a shopping centre located in Dublin, Ireland which comprises 80 stores and 20 restaurants. The centre opened on and is located near the junction of the M50 motorway and N4 road closely surrounded by Lucan to ...

is located at Junction 2. The road has three lanes and a bus lane in each direction between the M50 and Junction 5 which is also the start of the M4 motorway at Leixlip. The N4 was the only one of the main inter-urban national routes whose dual-carriageway section continued into the city centre; however, the section inside the M50 was re-classified as the R148 in 2012. Heading west, the PPP motorway section (see below) ends west of Kinnegad, and the motorway terminates 5 km further west; it continues as HQDC and bypasses

Mullingar Mullingar ( ; ) is the county town of County Westmeath in Ireland. It is the third most populous town in the Midland Region, Ireland, Midland Region, with a population of 22,667 in the 2022 census of Ireland, 2022 census. The Counties of M ...

. From the Mullingar bypass to Edgeworthstown, the road is a wide single-carriageway with hard shoulders. Between Edgeworthstown and

Longford Longford () is the county town of County Longford in Ireland. It had a population of 10,952 at the 2022 census. It is the biggest town in the county and about one third of the county's population lives there. Longford lies at the meeting of ...

, the road passes through Newtown Forbes and there is a lower standard single-carriageway road between Newtown Forbes and Roosky. Between Longford and Rooskey single carriageway continues at a higher standard. Dromod and Rooskey were bypassed in late 2007. This section of the road consists of three roundabouts and a Type 2 dual carriageway, i.e.: two lanes in each direction and no hard shoulder. The road resumes as a single carriageway with hard shoulders until it reaches

Carrick-on-Shannon Carrick-on-Shannon () is the county town of County Leitrim in Republic of Ireland, Ireland. It is the largest town in the county. A smaller part of the town located on the west bank of the River Shannon lies in County Roscommon and is home to th ...

, where it becomes a local urban road through five roundabouts, and passes over the

River Shannon The River Shannon ( or archaic ') is the major river on the island of Ireland, and at in length, is the longest river in the British Isles. It drains the Shannon River Basin, which has an area of , – approximately one fifth of the area of I ...

into

County Roscommon County Roscommon () is a Counties of Ireland, county in Republic of Ireland, Ireland. It is part of the province of Connacht and the Northern and Western Region. It is the List of Irish counties by area, 11th largest Irish county by area and Li ...

. The road becomes a high-quality single carriageway bypass 3 km outside of Boyle town, with periodic alternating overtaking lanes passing Lough Key Forest Park and Ballinafad until it reaches

Castlebaldwin Castlebaldwin or Bellanagarrigeeny () is a townland and small village in County Sligo, Ireland. The castle outside the village of Castlebaldwin is a fortified 17th-century house rather than a medieval castle, with gun slits in the walls and a ...

. From Castlebaldwin to

Collooney Collooney or Coloony () is a town in County Sligo, Ireland. Toponymy Collooney is thought to derive from . Reverend Terrence O'Rorke has previously also suggested ''Culmaine'', as Collooney is designated this way in such works as the ''Annal ...

the road is a Type 2 dual carriageway. Funding for the expansion of this section was announced in October 2018, and it opened in 2021. The road becomes near-motorway standard dual carriageway again at Collooney, approaching

Sligo town Sligo ( ; , meaning 'abounding in shells') is a coastal seaport and the county town of County Sligo, Ireland, within the western province of Connacht. With a population of 20,608 in 2022, it is the county's largest urban centre (constituting 2 ...

M4 motorway

The section from Leixlip to the west of Kinnegad is the M4

motorway A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway, and expressway. Other similar terms ...

. The first section of this motorway (Leixlip – Kilcock) was opened on 19 December 1994.

Tolled section of the M4 motorway

Under the Government announcement of the pilot projects on 1 June 1999 this project was to be assessed by the NRA for its suitability to be advanced as a Public-private partnership (PPP). Subsequently, the project was included as one of the projects approved under Tranche II of the PPP Roads programme as announced by the NRA in June 2000. The project involved the construction of 39 km of motorway from Kinnegad to Kilcock and is an extension of the Kilcock-Maynooth-Leixlip motorway on the N4/ N6 Sligo/Galway to Dublin route. The motorway bypasses the towns of Enfield and Kinnegad. The PPP contract was awarded in March 2003 to the EuroLink Consortium (SIAC Construction Ltd and Cintra - Concesiones de Infraestructuras de Transporte S.A.) and allows for them to collect tolls for 30 years from that date. This tolled section (from Kilcock to Kinnegad) opened on 12 December 2005, almost a year ahead of schedule. It is the second-most expensive toll road in Ireland (after the Dublin Port Tunnel). A toll of €3.50 (as of 2025) for cars is charged at a toll plaza just west of Kilcock and at smaller toll plazas at on and off-ramps at Enfield. Between Enfield and Kinnegad, no further access to the M4 is possible. Eurolink operates this tolling scheme, the first in Ireland not operated by NTR plc. From 2005 to 2007, Eurolink started to accept several tags issued by other motorways such as M1, M8, eTrip and Dublin Port Tunnel tags. On 14 June 2007 NTR plc joined the Nationwide Electronic Toll Payment System introducing their popular EazyPass tags on the system and allowing all other toll plazas in the country (different from those owned by NTR plc) to accept them, meaning that each toll company's electronic tag will work on all toll roads in the State. In the 1 July 2006 edition of the '' Meath Chronicle'' it was claimed that up to 10% of the €420 million road project had "to be ripped up and replaced" shortly after it opened due to rushed construction, however this cost would have had to be carried by the toll operators, not the state, as per the contract. The bypassed former N4 road has been reclassified as the R148.

Motorway reclassification

On 28 August 2009, the

Department of Transport A ministry of transport or transportation is a ministry responsible for transportation within a country. It usually is administered by the ''minister for transport''. The term is also sometimes applied to the departments or other government a ...

implemented the second round of proposed reclassifications of dual carriageways as motorways under the ''Roads Act 2007''. A short section of the N4 between Kinnegad (J12) and McNead's Bridge (J13) was affected by this. This extended the M4 westward by 6.8 km.

Junctions

The route begins as a dual carriageway at junction 7 of the M50, becoming a motorway after junction 5. It then becomes a dual carriageway after junction 13. After Mullingar, it becomes a regular

national road The National Road (also known as the Cumberland Road) was the first major improved highway in the United States built by the federal government. Built between 1811 and 1837, the road connected the Potomac and Ohio Rivers and was a main tran ...

. {, class="plainrowheaders wikitable" , - !scope=col, County !scope=col, km !scope=col, mi !scope=col, Junction !scope=col, Destinations !scope=col, Notes , - , rowspan="8",

County Dublin County Dublin ( or ) is a Counties of Ireland, county in Republic of Ireland, Ireland, and holds its capital city, Dublin. It is located on the island's east coast, within the Provinces of Ireland, province of Leinster. Until 1994, County Dubli ...

, - , , , bgcolor="dff9f9", 1 , bgcolor="dff9f9", – Dublin Airport,

Dublin Port Dublin Port () is the seaport of Dublin, Ireland, of both historical and contemporary economic importance. Approximately two-thirds of Ireland's port traffic travels via the port, which is by far the busiest on the island of Ireland. Locatio ...

Dún Laoghaire Dún Laoghaire ( , ) is a suburban coastal town in County Dublin in Ireland. It is the administrative centre of the county of Dún Laoghaire–Rathdown. The town was built up alongside a small existing settlement following 1816 legislation th ...

, bgcolor="dff9f9", Continues as R148 towards Dublin city centre and

Palmerstown Palmerstown (; officially Palmerston, see #Name origin and spelling, spelling) is a Civil parishes in Ireland, civil parish and suburb in western Dublin, Ireland on the banks of the River Liffey. It forms part of the South Dublin local authorit ...

. , - , , , 2 , ‒ Fonthill, Liffey Valley , , - , , , bgcolor="ffdddd", 2a , bgcolor="ffdddd", Ballyowen Lane , bgcolor="ffdddd", Westbound exit only. Exit lane runs parallel to mainline, ending at slip road at junction 3. , - , , , 3 , – Ballyowen,

Lucan Marcus Annaeus Lucanus (3 November AD 39 – 30 April AD 65), better known in English as Lucan (), was a Roman poet, born in Corduba, Hispania Baetica (present-day Córdoba, Spain). He is regarded as one of the outstanding figures of the Imper ...

, , - , , , 4 , – Lucan, Adamstown , , - , , , 4a , – Dodsboro, Kew Park , Only Dodsboro is signposted on eastbound approach. Exit lane runs parallel to mainline, ending at slip road at junction 5. , - , , , bgcolor="dff9f9", 5 , bgcolor="dff9f9", –

Celbridge Celbridge (; ) is a town and townland on the River Liffey in County Kildare, Republic of Ireland, Ireland. It is west of Dublin. Both a local centre and a commuter town within the Greater Dublin Area, it is located at the intersection of the ...

, Leixlip (westbound) , bgcolor="dff9f9", Heading eastbound, both destinations are followed by the ''(East)''

cardinal direction The four cardinal directions or cardinal points are the four main compass directions: north (N), south (S), east (E), and west (W). The corresponding azimuths ( clockwise horizontal angle from north) are 0°, 90°, 180°, and 270°. The ...

.
Continues as M4 motorway. , - , rowspan="5",

County Kildare County Kildare () is a Counties of Ireland, county in Ireland. It is in the Provinces of Ireland, province of Leinster and is part of the Eastern and Midland Region. It is named after the town of Kildare. Kildare County Council is the Local gove ...

, - , , , 6 , ‒ Celbridge (West), Leixlip (West) ,

Dunboyne Dunboyne () is a town in County Meath, Ireland, north-west of Dublin city centre. It is a commuter town for Dublin. In the 20 years between the 1996 and 2016 censuses, the population of Dunboyne more than doubled from 3,080 to 7,272 inhabitan ...

, - , , , 7 , ‒

Maynooth Maynooth (; ) is a university town in north County Kildare, Ireland. It is home to Maynooth University (part of the National University of Ireland and also known as the National University of Ireland, Maynooth) and St Patrick's College, Maynoo ...

Naas Naas ( ; or ) is the county town of County Kildare in Republic of Ireland, Ireland. In 2022, it had a population of 26,180, making it the largest town in County Kildare (ahead of Newbridge, County Kildare, Newbridge) and the List of urban ar ...

Straffan Straffan () is a village in County Kildare, Ireland. It is situated on the banks of the River Liffey, 25 km upstream of the Irish capital Dublin. As of the 2022 census of Ireland, 2022 census, the village had a population of 1,158, an over ...

, - , , , 8 , ‒ Kilcock
–

Clane Clane (; ) is a town in County Kildare, Ireland, from Dublin. With a population of 8,152 in 2022, it is the ninth largest town in Kildare and the 66th largest in Ireland. The town is on the River Liffey. Clane gives its name to the associate ...

, Enfield, Trim , - , , , bgcolor="dcdcfe" colspan="3" align="center", IE road sign symbol F-060

M4 Toll , - ,

County Meath County Meath ( ; or simply , ) is a Counties of Ireland, county in the Eastern and Midland Region of Republic of Ireland, Ireland, within the Provinces of Ireland, province of Leinster. It is bordered by County Dublin to the southeast, County ...

, , , 9 , ‒ Edenderry, Enfield , Toll at westbound entrance and eastbound exit slip roads. , - , County Kildare , , , colspan="3" align="center", Motorway Services Ireland

Enfield Service Area , - , County Meath , , , 10 , ‒ Kinnegad , , - , rowspan="8",

County Westmeath County Westmeath (; or simply ) is a Counties of Ireland, county in Republic of Ireland, Ireland. It is in the Provinces of Ireland, province of Leinster and is part of the Eastern and Midland Region. It formed part of the historic Kingdom of ...

, , , 11 , ‒

Athlone Athlone (; ) is a town on the border of County Roscommon and County Westmeath, Republic of Ireland, Ireland. It is located on the River Shannon near the southern shore of Lough Ree. It is the second most populous town in the Midland Region, Ir ...

Tullamore Tullamore (; ) is the county town of County Offaly in Republic of Ireland, Ireland. It is on the Grand Canal (Ireland), Grand Canal, in the middle of the county, and is the fourth most populous town in the Midland Region, Ireland, Midlands Reg ...

( N52) , - , , , bgcolor="ffdddd", 12 , bgcolor="ffdddd", ‒ Kinnegad, Galway (M6) , bgcolor="ffdddd", Westbound entrance and eastbound exit only. , - , , , bgcolor="dff9f9", 13 , bgcolor="dff9f9", ‒ Coralstown , bgcolor="dff9f9", LILO junction. Continues as N4 dual carriageway. , - , , , 14 , ‒ Killucan, The Downs , , - , , , bgcolor="ffdddd", , bgcolor="ffdddd", , bgcolor="ffdddd", LILO junction. Westbound entrance and eastbound exit only. , - , , , 15 , ‒ Tullamore,

(East) , , - , , , 16 , ‒

Dundalk Dundalk ( ; ) is the county town of County Louth, Ireland. The town is situated on the Castletown River, which flows into Dundalk Bay on the north-east coast of Ireland, and is halfway between Dublin and Belfast, close to and south of the bor ...

, Mullingar (Centre) , , - , , , 17 , ‒ Castlepollard, Mullingar (West) , Mullingar Hospital
Continues as N4 regular national road.

Bypasses

* Palmerstown – 1984 * Lucan – 1988 * Leixlip, Maynooth, Kilcock – 1994 * Mullingar – 1994 * Longford – 1995 * Drumsna, Jamestown – 1997 * Collooney, Ballisodare – January 1998 * Boyle, Ballinafad – 1998–1999 * Sligo (partial) – September 2005 * Enfield, Kinnegad – December 2005 * Edgeworthstown – June 2006 * Dromod, Roosky – December 2007 * Castlebaldwin – August 2021

Upgrades

In July 2009, an upgrade of the section between the M50 junction and the Leixlip interchange was completed. In this section the road is three lanes in each direction, the median crossings were removed and the junction with the R120 is a fully grade-separated junction. Private accesses and some left turns remain which prevents the section from being designated a

. The speed limit is 80 km/h. There are currently no signal-controlled junctions on the N/M4 between the M50 motorway and the Sligo through-pass. In 2013, a 5 km stretch of dual carriageway with at-grade crossover junctions between the M4 and the Mullingar bypass was upgraded to HQDC. Construction of a 2+2 road at the 15 km stretch between Collooney and Castlebaldwin began in 2019 to improve

road safety Road traffic safety refers to the methods and measures, such as traffic calming, to prevent road users from being killed or seriously injured. Typical road users include pedestrians, cyclists, Driving, motorists, passengers of vehicles, and p ...

. The road was opened on 18 October 2021.

Planned improvements to the route

* Mullingar to Longford; 40 km dual carriageway, including bypass of Longford Town. As of November 2023, route corridor options have been presented, awaiting a decision on the preferred route corridor. * Dromod to

21 km, including 10 km bypass of Carrick-on-Shannon. At planning stage, as of November 2023.
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References

Sources

Roads Act 1993 (Classification of National Roads) Order 2006
–

Roads Act, 1993 (Classification of National Roads) (Kilkock – Kinnegad Route) Order, 2003

Eurolink Motorway M4 website
{{DEFAULTSORT:N4 Road (Ireland) 04 Roads in County Dublin Roads in County Kildare Roads in County Meath Roads in County Westmeath Roads in County Longford Roads in County Leitrim Roads in County Roscommon Roads in County Sligo