The woman in her 30s who was seriously injured in an attack on Linen Hall St this afternoon has died.
A man in his 40s was arrested by Dundalk Gardai in relation to the incident.
He is currently being questioned at Dundalk Garda Station.
Linen Hall Street remains closed.
The woman was rushed to Hospital in Drogheda following the incident but has since passed away.
The Irish Daily Mirror is reporting that the woman was originally from Lithuania.
UPDATE AT 5:25pm: A Garda spokesperson said: "Gardaí at Dundalk Co Louth are investigating a stabbing incident which occurred at Linen Hall Street, Dundalk Co Louth (Apartment Block) at approximately 2.45pm this afternoon, Tuesday September 18th.
"A female in her 30s was seriously injured, she was taken to Our Lady of Lourdes Hospital in Drogheda and was subsequently pronounced dead a short time later.
"A Post Mortem examination will now take place at Our Lady of Lourdes Hospital in Drogheda. The scene is preserved for a technical and forensic examination and an incident room has been established at Dundalk Garda Station.
"The office of the State Pathologist and Coroner have been notified. A male in his 40s has been arrested in connection with this investigation and is currently detained at Dundalk Garda Station under the provisions of Section 4 – Criminal Justice Act 1984."