|Length:||96.5 km (60 miles)|
|Meets:||N18, R926, R510, R526, N21, R516, R518, R515, R522, R580, R581, R930, N72, R619, R620, R638, R617, R635, R846, R847, N8, N22|
|Route outline (key)|
The first 9 km – running southwestward from a grade-separated junction with the M7 and N18 at the Rossbrien Interchange – is designated as the M20. At junction 5 the mainline ahead is the N21, and N20 traffic turns off left, to briefly rejoin the original, pre-motorway route from Limerick. The modern road is a high-quality single-carriageway route and within 2.5 km there begins a 5-km-long stretch of new build, bypassing the village of Croom. After Croom, it resumes its original course.
Following this, the route continues generally southward, through Charleville and Buttevant towards Mallow. There's a brief section of dual carriageway after meeting the N72, while the N20 bypasses the town to the west. From here, it runs on New Mallow Road, which, as the name suggests, is a high-quality replacement of the original road, initially single-carriageway, then a dualled and grade-separated route towards Cork.
On reaching Blackpool, a suburban district of Cork city, the N20 turns right at a light-controlled junction and follows the dual-carriageway North City Link Road down to the quays in the city centre. Immediately after crossing the River Lee, we turn left to follow Lavitt's Quay for 140 m to reach the terminus of the route at a crossroads junction with the N8 and N22.
The N20 was originally part of the T11 (which also included the basic route of the N18 and N17) and started at the junction of O'Connell Street and Sarsfield Street in the centre of Limerick at a point with the N7, N18 and N24. The old road is now the R526.
The construction of Childers Road moved the start of the N20 to outside the city centre, meeting what was the N7 at an at-grade roundabout to the east. It followed what is now the R509 along the M20, which was then an all-purpose road. In 2010, the various upgrades around Limerick, including the opening of the Shannon Tunnel, caused the N20 to be truncated to its current start point.
Most of the N20 between Mallow and Cork is the New Mallow Road. This runs on a completely different alignment to the original road.
Irish Statute Book
- Roads Act 2007 (Declaration of Motorways) Order 2009 - This instrument converts the following sections of the N20 to motorway: Limerick to Attyflin (also known as the N20/N21 Junction)