A woman (30) and her three young children had to jump to safety from a bedroom window.
All four are believed to be uninjured but shocked by their experience.
The scene has been preserved and will be examined by Garda forensic experts.
Indications are that it is not linked to a gangland feud.
The fire brigade were called by local people who saw flames coming from the door of the semi-detached house in St Laurence’s Park at approximately 9.40pm.
Drogheda Fire Service responded and extinguished the blaze.
It is believed the family had moved in last month. The children are all understood to be primary-school age.
Gardaí said the cause of the fire was under investigation and will include whether an item with some form of an accelerant was used to start the fire – damage was caused to the door and porch.
Flames were first seen coming from the entrance to the home, which is at the side of the three-bedroom property. When neighbours rushed to see if they could help, they saw the woman and three boys jumping from a first-floor bedroom window.
The family were assessed by ambulance and paramedics at the scene and did not require hospital treatment.
Gardaí sealed off the house and they are appealing for witnesses to contact them at Drogheda Garda station (041 9874200) or the Garda Confidential Line (1800 666 111).
