The N4 Realignment -Collooney to Castlebaldwin Road scheme in Co. Sligo is 14.5km in length and commences just south of Collooney.
- 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 Junctionon the mainline, (Drumfin/Cloonlurg Junction);
- One at-grade roundabout Junction on the mainline, (Castlebaldwin Junction);
- Three at-grade roundabout Junction 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 scheme will bypass the townlands of Lackagh, Drumfin, and Castlebaldwin. A Type 2 Dual Carriageway is planned from the start of the scheme at the N4/N17 Toberbride Roundabout to the Castlebaldwin Roundabout, a total length of 13.625km.
The first 2.58km is online and is an upgrade from the existing single carriageway to a Type2 Dual carriageway. At Ch. 2+500 the scheme veers offline, west of the existing N4 road until crossing back over the existing N4 to the east side at Ch. 10+200, and continues to the Castlebaldwin Roundabout at Ch. 13+600.The final section of the route from the Castlebaldwin Roundabout south to its termination point at the tie in location with the existing network(at Ch. 14+500)will be a Type 1 Single Carriageway. The scheme includes approximately 8km of side roads and farm access roads, 12 No. primary Bridge Structures and two Major Roundabouts.
As part of the project a new 3km cycleway from Toberbride will be constructed and will join the existing N4 at Doorly. The new road will pass through the townlands of Collooney, Toberbride, Mullaghnabreena, Ardcurley, Cloonamahan, Doorly, Knocknagroagh, Drumfin, Cloonlurg, Carrowkeel, Carrownagark, Kingsbrook, Aghalenane, Ardloy, Springfield, Tawnagh, Cloonymeenaghan, Sheerevagh, Cloongad, Drumderry, Castlebaldwin, Cloghoge Upper and Cloghoge Lower.