A 3-year-old boy was passenger in a car which collided with another vehicle at Annamarron, on the main N2 Dublin to Derry Road at around half past six last night.
A 36-year-old woman who was driving the car was critically injured and flown by Air Ambulance to Tallaght Hospital in Dublin.
Two women in the second car were taken to Our Lady of Lourdes Hospital in Drogheda.
Gardaí are appealing for any witnesses to come forward and are anxious to speak to a lorry driver who stopped at the scene of the collision.
Meanwhile, a motorcyclist died when his bike collided with a tree on the Kilmacanoge to Roundwood Road in Co Wicklow.
He was pronounced dead at the scene and his body removed to St. Columcille’s Hospital in Loughlinstown where a post mortem will take place.
Both roads were closed for forensic examinations.
Gardaí are appealing for witnesses to both collisions.
