A 48-year-old man from county Louth has died in a three-car crash last night.
Preliminary indications are that the man's car may have been travelling southbound on the northbound carriageway.
Gardai have appealed for witnesses who have not yet spoken to them, to make contact.
A woman in the second car has been taken to hospital with multiple fractures while a mother and her 11 year old daughter who were in the third vehicle are said to be ‘shocked’ but otherwise unharmed.
Gardai have asked that anyone who was on the northbound carriageway last night and witnessed the incident to contact them at Ardee garda station.
The section of the M1 motorway in county Louth where the crash occurred - between junctions 15 and 16 - has now been reopened.
It had been closed to facilitate garda forensic collision investigators to complete their work.