National Primary Route 21

Status : Planned

M21 Motorway Logo


Will open : 2027

Motorway: 0 km (16.7 km by 2027)
HQDC: 1.3 km (0 km by 2027)
D2AP: 3.8 km (17.3 km by 2030)
Single Carriageway: 79.6 km (49.4 by 2030)

The N21 is the main route from Limerick to Kerry. It starts by spitting off the M20 motorway southwest of Limerick and heads through the rural part of the county before passing around the Kerry town of Castleisland. The N23 to Killarney splits off to the south while the N21 continues west to Tralee, terminating on the 2013 Tralee Bypass. Here the route meets the N22 and N69 at a roundabout. The route serves a string of small towns along the way: the tourist town of Adare, Rathkeale, Newcastle West, and Abbeyfeale.

The road has seen little improvement over the years. Most of the single carriageway from Tralee to Abbeyfeale has been replaced in the last 20 years and there is a short dual carriageway stretch around Castleisland, but the rest of the route remains underdeveloped. Chronic traffic issues remain unresolved at Adare, which sees tourist, commuter and long distance traffic mingling on the main street lined with picturesque thatched cottages. About 10 years ago, an Adare bypass was planned to run south of the town, but was refused planning permission, and the 2008 economic crisis put the idea on ice for a decade. Around 2015 however, an EU-funded plan to create an upgraded route from Limerick to the important River Shannon port of Foynes was unveiled. Sensibly, this would run past Adare, meaning that the port route and Adare bypass could be provided with one road. In 2017 further details were announced - the Adare segment would run north of the town as far as Rathkeale and would be motorway. It would measure 16.7 km in length. From there, the rest of the project would provide a grade-separated single carriageway northwest to Askeaton and onward to Foynes. It is expected that this part will be built by 2025 and it will solve the greatest traffic and safety issues on the N21.

As for the rest of the route, there used be a plan to dual from Rathkeale as far as Abbeyfeale. This would complete an upgrade of the whole N21 - there would then be motorway from Adare to Rathkeale, dual carriageway from Rathkeale to Abbeyfeale, and good quality single carriageway from Abbeyfeale to Tralee. Unfortunately this idea seems to have disappeared and the last time any information was revealed on this it was merely short single carriageway bypasses of Newcastle West and Abbeyfeale. The low standard parts in between would not be improved.

Update 12/07/2019: A planning application for the M21 Adare-Rathkeale and N69 Rathkeale to Foynes schemes is expected by the end of the year. Newcastlewest and Abbeyfeale bypasses are at Feasibility Study. It is likely these would be small-scale, short bypasses. A full Rathkeale-Abbeyfeale scheme is now not planned until after 2027.

Update 07/02/2021: The oral hearing into a planning permission for the M21 Adare-Rathkeale scheme will run from 8th-18th February. This will deal with the EIS (Environmental Impact Statement) and objections and is a step towards the final decision. No date for the latter has been confirmed, however.
There are separate websites for the route options for the Newcastlewest and Abbeyfeale bypasses.

Update 05/10/2021: Here is the latest update on the Adare bypass courtesy of
This scheme was published in December 2019. An Bord Pleanala requested additional information which was submitted in September 2020 and also placed on public display. ABP held the Oral Hearing for the scheme over 11 days in February 2021. A decision on planning is expected in Q4 2021. Work is progressing on the Phase 5 (Enabling and Procurement) documents to facilitate early construction of the Adare Bypass in advance of the 2027 European Ryder Cup, assuming statutory approval is achieved.

Update 09/11/2021: The Preferred Routes for the Newcastle West and Abbeyfeale bypasses have been decided. Click here for the Newcastle West virtual consultation room. The map can be found under "8.Preferred Route Corridor". It passes to the north of the town and may include a link road to R521 which would improve connectivity to the town centre. It will measure about 7.25 km and the standard will be dual carriageway.

The Abbeyfeale route is here. It passes to the south of the town and is much straighter. It will be 6.2 km long and also dual carriageway.

Both schemes should be ready for submission to the planning board by 2023.

Update 18/02/2022: The M21/N69 Adare Bypass/Foynes road has had its planning decision postponed many, many times. It now seems a result will finally appear "next month", i.e. in March. Adare has planned a bypass for decades, and the scheme will effectively create an entirely new route between Limerick and its port at Foynes, via the M20, new M21 and new N69 dual carriageway.

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Origin M20/M21 Junction, Patrickswell, Limerick
Terminates N21/N22/N69 roundabout, Tralee, Kerry
Places Served Adare, Rathkeale, Newcastle West, Abbeyfeale, Castleisland, Tralee
Routes Spawned M20, N22, N69
Intersects N23


Distances in brackets are upgrades of existing stretches.

Section km Opening Date Standard
Patrickswell to Adare (N20/N21 Patrickswell to Limerick) 1.3 2001-05 HQDC
Castleisland to Abbeyfeale 6.6 2006-05 SC
Castleisland BP (N21 section) 3.8 2010-10-22 D2AP
Adare to Rathkeale 16.7 2027 M
Newcastlewest BP 2027? D2AP
Abbeyfeale BP 2027? D2AP
Rathkeale to Abbeyfeale 33 2030+ D2AP

MAP OF M21 :