County Louth (; or Lughbhadh) is a county in Ireland. It is part of the Border Region and is also located in the province of Leinster. It is named after the town of Louth. Louth County Council is the local authority for the county. The population of the county is 122,897 according to the 2011 census.
The official spelling in Irish, Lú, is derived from Lughbhaidh - the Celtic pagan god Lugh, whose festival is celebrated at Lughnasadh (Lúnasa). This is a county steeped in myth, legend and history, going back to the pre-historic days of the Táin Bó Cúailnge (Cooley Cattle Raid, see Cú Chulainn). Later it saw the influence of the Vikings as seen in the name of Carlingford Lough. They also established a longphort at Annagassan in the ninth century. At this time Louth consisted of three sub-kingdoms each subject to separate over-kingdoms: Conaille (Ulaidh); Fir Rois (Airgialla); and, the Fir Arda Ciannachta (Midhe). The whole area became part of the O'Carroll Kingdom of Airgialla (Oriel) early in the twelfth century.
The Normans occupied the Louth area in the 1180s, and it became known as English Oriel, to distinguish it from the remainder (Irish Oriel) which remained in Irish hands. The latter became the McMahon lordship of Oriel of Monaghan. There are a number of historic sites in the county, including religious sites at Monasterboice and Mellifont Abbey. In the early fourteenth century the Scottish army of Edward Bruce (brother of Robert of Bannockburn fame) was defeated in the Battle of Faughart near Dundalk, Edward losing not only his claim to the High Kingship Of Ireland, but also his life. The sixteenth and seventeenth centuries featured many skirmishes and battles involving Irish and English forces, as it was on the main route to 'the Moiry Pass' and the Ulster areas often in rebellion and as yet uncolonised. Oliver Cromwell attacked Drogheda in 1649 slaughtering the Royalist garrison and hundreds of the town's citizens (Siege of Drogheda). Towards the end of the same century the armies of the warring Kings, James and William, faced off in South Louth during the build-up to the Battle of the Boyne - the battle takes its name from the river Boyne which reaches the sea at Drogheda.
In 1798 the leaders of the United Irishmen included Bartholomew Teeling, John Byrne and Patrick Byrne, all from Castletown; Anthony Marmion from Louth Town & Dundalk,Anthony McCann from Corderry; Nicholas and Thomas Markey from Barmeath, Arthur McKeown, John Warren and James McAllister from Cambricville. They were betrayed by informers, notably a Dr. Conlan, who came from Dundalk, and an agent provocateur called Sam Turner, from Newry. Several leaders were hanged.
In 1816 the Wildgoose Lodge Murders took place in the west of the county.
The priest and scientist Nicholas Callan (1799–1864) was from Darver.
For more information, see the EN Wikipedia article County Louth. especially the section "Geography and political subdivisions" and its subsection "Towns and villages"