The M3 starts near the Dublin - Meath border at Junction 4 south of Clonee and is joined to the M50 by 5 km of all-purpose high-quality dual-carriageway road, the N3. It is privately operated by the Eurolink consortium and has two toll plazas between Clonee and Kells. One is north of Navan, the other between Dunshaughlin and Clonee and the current charge per car payable at each is €1.40. After 50 km the motorway ends at a roundabout junction with the N52 Kells Bypass and the all-purpose N3 resumes.
- The M3 between junctions 4 and 5 is a redesignated section of the N3
- The M3 north of junction 5 opened at 16.00 on 4 June 2010