Ballylahan Castle is a tower house and National Monument located in County Mayo, Ireland.

[1][2] Ballylahan Castle is located 2.3 km (1.4 mi) northeast of Strade, on the south bank of the River Moy.

[3] This castle was constructed in 1260 by Jordan de Exeter, Sheriff of Connacht and was the ancient seat of the Mac Siúrtáin (MacJordans).

[4][5] The castle came under attack in 1316 by the King of Connacht, Fedlim Ó Conchobair and was almost destroyed.

[6][7] The main entrance was in the east and it was flanked by two circular towers, of which only one remains.