N4 Collooney to Castlebaldwin Road Development


Current Status

  • An Bord Pleanála approved the Project in July 2014
  • All advance works complete
  • Land purchase and accommodation works agreements 95% Complete
  • Construction contract awarded to Roadbridge Ltd. in January 2019
  • Construction works ongoing
  • Expected completion Q4, 2021

Project Location

The N4 National Primary Route is part of the East/West road corridor linking Ireland’s largest transportation node (Dublin) with the largest transportation node in the North-West (Sligo).  It measures c. 34.8km in County Sligo of which c. 11.6km between Sligo Town and Collooney is Type 1 Dual Carriageway with c. 8.8km south of Castlebaldwin having already been realigned to Standard Single Carriageway standard (Part of the N4 Curlews Bypass).

The Proposed Road Development is one of the biggest and most complex infrastructural projects ever proposed to be developed in County Sligo.  It constitutes the remaining portion of the N4 in Co. Sligo requiring improvement and measures approximately 14.71km in length passing through the townlands of Rathrippin, Collooney, Toberbride, Mullaghnabreena, Ardcurley, Cloonamahan, Doorly, Knocknagroagh, Drumfin, Cloonlurg, Carrowkeel, Carrownagark, Kingsbrook, Aghalenane, Ardloy, Springfield, Tawnagh, Cloonymeenaghan, Sheerevagh, Cloongad, Drumderry, Annaghcor, Castlebaldwin, Cloghoge Upper and Cloghoge Lower.

Project Description

This Road Development Project comprises of the following:

  • 2.58km of widening and improvement of the existing N4 Single Carriageway to a Type 2 Dual Carriageway from the existing N4/N17 Toberbride roundabout in Collooney to Doorly Td.;
  • 12.12km of offline realignment from Doorly Td. to Cloghoge Lower Td., (11.23km between Doorly Td. and Castlebaldwin Junction is proposed to be Type 2 Dual Carriageway and the remaining tie-in section is proposed to be Type 1 Single Carriageway);
  • New side roads and upgrading of existing local roads;
  • One Compact Grade Separated Junction on the mainline, (Drumfin/Cloonlurg Junction);
  • One at-grade roundabout junction on the mainline, (Castlebaldwin Junction);
  • Three at-grade roundabout junctions on sideroads; (Toberbride East Junction, Doorly Junction, Cloonamahon Junction);
  • Four road overbridges (Toberbride, Knocknagroagh, Drumfin North, Drumfin South);
  • Six road underbridges (Doorly North, Doorly South, Carrownagark, Kingsbrook, Ardloy and Tawnagh);
  • Two river bridges (Lough Corran Outflow/Turnalaydan River Bridge and Drumfin River Bridge);
  • Culverts and associated diversions of existing minor watercourses and drainage ditches;
  • All necessary drainage works, diversion of services and utilities, environmental mitigation works and accommodation tracks.

The first 2.58km of the development at the Collooney end is online and consists of an upgrade of the existing N4 Single Carriageway to a Type 2 Dual Carriageway.  It then veers offline, to the west of the existing N4 National Primary Road for approximately 7.62km where it crosses the existing N4 at Ardloy Td. (Ch10,200 approximately) to the east side and continues in a southerly direction to the east of Castlebaldwin Village in Castlebaldwin Td. where a roundabout shall be constructed.  (Castlebaldwin Junction).  A Type 1 Single Carriageway, which will be commensurate with the existing improved section to the south known as the Curlew Mountain Bypass, shall be constructed from Castlebaldwin Junction in a southerly direction to the tie-in location with the existing N4 National Primary Road in the townland of Cloghoge Lower Td., a total length of approximately 0.9km.

In order to provide access/egress from the local road network/dwellings/farm accesses along the eastern side of the online upgrade section, a single carriageway parallel access road (Eastern Parallel Link) is proposed to the east of the existing N4 between Toberbride Td. and Doorly Td.  This proposed access road shall connect to the eastern arm of the N4/N17 Toberbride Roundabout and the existing N4 at Doorly Td. just to the north of the local road (L1302-0) junction with the existing N4.

In order to provide access/egress from the local road network/dwellings/farm accesses along the western side of the online upgrade section, a single carriageway parallel access road (Western Parallel Link) is proposed to the west of the existing N4 between Cloonamahan Td. and Doorly Td.  This proposed access road shall be linked to the eastern parallel road via a proposed underbridge at Doorly Td.

An overbridge shall be provided at Toberbride Td. from the proposed Eastern Parallel Link Road to facilitate access/egress for the existing local road network.

Dedicated Project Website

The N4 Collooney to Castlebaldwin Road Project has a dedicated website https://www.n4realignment.ie/ where you will find the following:

  • Contacts for the construction project
  • Project construction updates and newsletters
  • Traffic management updates, etc.

Project Route Map


Project Development - Post Planning Approval

The planning and design of the N4 Collooney to Castlebaldwin Road Project was developed in accordance with the National Roads Authority (Now Transport Infrastructure Ireland) Project Management Guidelines.  This document outlines the framework for the phased approach to the development, management and delivery of national road schemes.  The 2010 version which applied largely to this Project set outs the progression of a National Road Realignment Project into seven phases as outlined below:

Project Guidelines

This Project was approved by An Bord Pleanála in July 2014.  The Compulsory Purchase Order was confirmed by Sligo County Council (SCC) in August 2014.


Phase 5 Advanced Works, Construction Document Preparation, Tender and Award

Following An Bord Pleanála’s confirmation of the Environmental Impact Statement (EIS) and Compulsory Purchase Order (CPO), Sligo County Councils National Road Project Office continued to manage the development of the Project.

The Notice to Treat and Notice to Enter were issued to affected landowners in Q1, 2015 to enable Advance Works Contracts to commence.  The following Advance Works Contracts were prepared, tendered and managed directly by Sligo County Council (SCC) National Road Project Office (NRPO) and completed from 2015 to 2017:

  • Archaeological investigation and preservation by record
  • Ground Investigation
  • Service Diversions which included 110kv diversion works and construction of a 220kv pylon
  • Detailed topographical survey
  • Topographical Check Survey
  • Building demolition
  • Fencing and tree clearance

View Advanced Works Photos

This also enabled land purchase to commence.  The Scheme involves the acquisition of 181.5 hectares of land (135 landowners) which included 14 dwelling houses.  Agreement has been reached with over 95% of landowners to date in relation to compensation and accommodation works packages.  Sligo County Council wishes to take this opportunity to acknowledge the goodwill and co-operation of the affected landowners throughout the progression of this Project.

A tender process was undertaken to appoint Consultants to progress remaining Phases 5 works in addition to provision of technical support to Sligo County Council for Phase 6 and 7 of the NRA Project Management Guidelines.  Halcrow Barry (Now Barry Transportation Ltd.) were awarded this Contract in Q2, 2017.

A Contract Notice for the main construction works was published on e-Tenders and the associated Official Journal of the European Union (OJEU) website commencing the pre-qualification process for a construction contractor in Q4, 2017.  Seven Candidates submitted Suitability Assessment Questionnaires by the closing date in Q1, 2018.  Following assessment, five Candidates were shortlisted and invited to tender in Q2, 2018.  Tenders were received from four of the five Candidates before the deadline for tender receipt in Q3, 2018.  The fifth Candidate withdrew from the tender process in May 2018.  A detailed tender assessment was undertaken to determine the winning Candidate. 

Sligo County Council sought the necessary approvals to award the contract in Q4, 2018.  Approval was granted to award the construction contract to Roadbridge Ltd. in January 2019.

Phase 6 Construction and Implementation

The N4 Collooney to Castlebaldwin Road Project is currently at Phase 6 – Construction and Implementation.  Roadbridge Ltd. has mobilised and commenced with the establishment of site compounds at Toberbride Business Park and Drumfin South off the local road L-1502-32.  Extensive archaeological and ecological surveys were initially carried out prior to the main construction works and are continuing at various locations throughout the site.  Site clearance and demolition works are also ongoing.  Haulage roads, temporary diversions and Bulk earthworks are being progressed. 


Objectives of the Road Development:

The provision of the realignment provides the following key benefits:

  • To improve the N4 route to modern day standards including the provision of safe overtaking and appropriate road width;
  • To improve safety along the existing roads and at junctions/accesses;
  • To provide a high quality road for strategic routes with reserve capacity for future demand;
  • To assist in improving the competitiveness and efficiency of the economy both locally and nationally;
  • To reduce travel times and improve access to the north-west region;
  • To provide a corridor of transport infrastructure that will encourage and support existing investment and employment in Sligo and the Northwest;
  • Improve transport infrastructure for local traffic;
  • To reduce environmental and social impacts on the local residents and communities along the existing N4.
  • To support government plans and policies in relation to transport and spatial development in the West of Ireland.


The scheme was designed in-house by Sligo County Council's National Road Project Office Team so the lead witnesses at the An Bord Pleanála Oral Hearing (see below) were Sligo County Council Road Design Engineers.

The Environmental Impact Statement (EIS) was also produced by the Sligo County Council's National Road Project Office Team whom also coordinated and managed the environmental assessment input from groups of specialist sub-consultants whose disciplines related to Traffic Modelling, Geotechnical, Flood Risk, Socio-Economic, Non-Agricultural Property, Noise and Vibration, Air Quality, Landscape and Visual, Agricultural Property, Flora, Fauna and Fisheries, Soils and Geology, Hydrology and Hydrogeology, Archaeology, Architecture and Cultural Heritage.  Each sub-consultant also provided evidence at the Oral Hearing relative to their various disciplines. 

The detailed and complex Compulsory Purchase Order (CPO) was also prepared by members of the in-house National Road Project Office team.

Statutory Procedure and Consent Approvals:

In early December 2013, correspondence was received from the NRA (now TII) conveying approval to publish the Compulsory Purchase Order (CPO), Environmental Impact Statement (EIS) and Natura Impact Statement (NIS) and to submit the N4 Collooney to Castlebaldwin Proposed Road Development to An Bord Pleanála for planning approval.  The publication of Statutory Notices in Local and National press on the 19th and 21st December 2013 commenced this process.  The CPO, EIS and NIS were placed on Public display and submissions or observations were requested to be made by interested parties to An Bord Pleanála.

The Board subsequently held an Oral Hearing from the 28th to the 30th of April in the Castledargan Hotel, Ballygawley.  This provided a forum for the cross examination of the aforementioned witnesses by those who had made bona-fide submissions and the Inspector delegated by the Board to conduct the hearing. 

Following this the Board, having considered the objections made and the report of the Inspector who conducted the Oral Hearing approved (on the 22nd of July, 2014) the Proposed Road Development under section 51 of the Roads Act, 1993 (as amended).  The Board also confirmed the CPO for the Proposed Road Development.  Notice of Confirmation of the CPO was published in the Sligo Weekender on the 28th August 2014 with the CPO becoming operative 3 weeks later.  The eight week period during which an appeal to the High Court could take place ended on the 24th October, 2014.


Sligo County Council has appointed Roadbridge Ltd. to undertake the construction of the Project.

Should you have any queries or observations/comments in relation to the construction works and associated traffic management, please contact Roadbridge Ltd. on freephone number 071 91 67299.


View Environmental Impact Statement for the Proposed Road Development

View Briefs of Evidence for the Proposed Road Development 

View An Bord Pleanála for the Proposed Road Development Oral Hearing 

View Supplementary Information for the Proposed Road Development Oral Hearing



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