County Carlow is a county in Ireland. It is part of the South-East Region and is also located in the province of Leinster. It is named after the town of Carlow, which lies on the River Barrow.
Carlow, or "Catherlough" originally part of the Norman Palantine-county of Leinster, became a separate county probably around 1306. At that time it was larger than today, extending to and including the coastal area around Arklow, though control of this area became disputed with the Irish chieftains of the area. These areas were given over to County Wicklow in 1606-07.