Louth is Ireland's smallest county, hence its moniker, the Wee County. In the 5th and 6th centuries, it was at the centre of ecclesiastical Ireland, with wealthy religious communities at the monastery at Monasterboice and the Cistercian abbey at Mellifont. The 12th-century Norman invaders were responsible for the development of Dundalk and the two towns on opposite banks of the Boyne that united in 1412 to become what is now Drogheda, the county's largest town.
In the north, the picturesque Cooley Peninsula is separated from County Armagh, Northern Ireland, by the waters of Carlingford Lough, home to the lively little town of Carlingford, which retains its medieval architecture.
While Louth can easily be covered as a day trip from Dublin, you'll get more from your visit by spending some time exploring the county.