Croaghaun, County Carlow, Mountain summit in County Carlow, Ireland

Croaghaun (Irish: Cruachán) is a mountain in County Carlow, Ireland, and the most northerly summit of the Blackstairs Mountains. Its summit reaches 451 metres above sea level, standing 110 metres above the surrounding terrain, with a base width of about 2.4 km. The terrain is hilly to the southeast and flatter to the northwest, and the surrounding area is mainly grassland.

Croaghaun is the northernmost summit of the Blackstairs Mountains, a range that forms the boundary between County Carlow and County Wexford. The summit rises 451 metres above sea level, with 110 metres of prominence over the surrounding terrain and a base width of about 2.4 kilometres. The nearest larger settlement is Muine Bheag, 13.7 kilometres to the west.

The mountain's Irish name is Cruachán, anglicised as Croaghaun; both forms appear on maps and in local speech. It is the most northerly summit of the Blackstairs Mountains, a range that runs along the County Carlow–County Wexford border.

Several marked trails lead to the summit with access points along local roads. Visitors should be prepared for changeable weather and bring appropriate gear for hillwalking.

Croaghaun is the most northerly summit of the Blackstairs Mountains, and its Irish name is Cruachán. The peak rises 451 metres above sea level, with a prominence of 110 metres over the surrounding terrain and a base width of about 2.4 km. The nearest larger settlement is Muine Bheag, some 13.7 km to the west.