Map - County Carlow (County Carlow)

County Carlow (Contae Cheatharlach) is a county located in the South-East Region of Ireland, within the province of Leinster. Carlow is the second smallest and the third least populous of Ireland's 32 traditional counties. Carlow County Council is the governing local authority.

The county is named after the town of Carlow, which lies on the River Barrow and is both the county town and largest settlement, with over 40% of the county's population. Much of the remainder of the population also reside within the Barrow valley, in towns such as Leighlinbridge, Bagenalstown, Tinnahinch, Borris and St Mullins. Carlow shares a border with Kildare and Laois to the north, Kilkenny to the west, Wicklow to the east and Wexford to the southeast.

Carlow is known as "The Dolmen County", a nickname based on the Brownshill Dolmen, a 6,000-year-old megalithic portal tomb which is reputed to have the heaviest capstone in Europe, weighing over 100 metric tonnes. The town of Carlow was founded by the Normans in 1207 and the county was shired shortly thereafter, making it one of the oldest counties in Ireland. During the 14th century, the county was the seat of power of the Kingdom of Leinster, as well as the capital of the Lordship of Ireland from 1361 to 1374.

The county was named after the town of Carlow, which is an anglicisation of the Irish Ceatharlach. Historically, it was anglicised as Caherlagh, Caterlagh and Catherlagh, which are closer to the Irish spelling. In the 19th century, John O'Donovan, a scholar working with Ordnance Survey Ireland, hypothesised that the origin of the name was Ceatharloch (meaning "quadruple lake"), since ceathar means "four" and loch means "lake". It is therefore directly translated as "Four lakes". This was accepted by the foremost etymologist of the time, PW Joyce, as the definitive origin of the name; although Joyce noted there was no evidence to suggest that these lakes ever existed in the area.

It is today believed that the first part of the name derives from the Old Irish word cethrae ("animals, cattle, herds, flocks"), which is related to ceathar ("four") and therefore signified "four-legged". The second part of the name is the ending -lach, meaning that "Ceatharlach" referred to a "place of cattle or herds". As the local dialect of Irish evolved, the "th" phoneme became obsolete. Consequently, by the 13th century the pronunciation of the name would have been much closer to its modern anglicised form. Surviving texts from the 15th and 16th centuries which spell the name as "Carelagh" and "Kerlac" seem to reflect this change in pronunciation.