Louth has a long history (and prehistory) of human occupation, dating back to the Mesolithic. The quarries at Mell, near Drogheda, furnished the only Palaeolithic tool ever found in Ireland, but it is thought that this was originally made and dropped on dry land in the Irish Sea basin and carried up into County Louth by the Scottish ice.
Louth’s archaeological heritage is protected under the National Monuments Acts 1930 to 2004.
Record of Monuments and Places (formerly the Sites and Monuments Record)
There are more than 1500 'sites' recorded in the Record of Monuments and Places for County Louth, under the National Monuments Acts. More than 20 of these are National Monuments in the ‘traditional’ sense, though the current interpretation of the law, that any sites in the ownership of guardianship of a statutory body is a national monument, would mean a very much higher (but so far uncalculated) total.
You may view the Sites and Monuments record for Louth at archaeology.ie.