The Navan accident happened at about half past nine last night when the moped the woman was driving was struck by a car at Kilberry.
The victim, who was in her 50s, was removed to Navan General Hospital where a full post mortem is expected to take place later today.
Gardaí are appealing for anyone who was in the area at the time to come forward.
A 32-year-old man has also died after a single car crash in Northern Ireland. He was the passenger in a car that crashed on the Carryduff Road in Co. Down.
A 20-year-old man has been arrested, and the road has been closed for a technical examination.