Castell Moel (also known as Greencastle, Green Castle, Humphreys Castle, or Castle Mole) is the remains of a 16th-century fortified manor house in the community of Llangain in Carmarthenshire, Wales, and also a medieval motte about 600 yards (550 m) to the south of the manor house. The remains are approximately 2.5 miles (4.0 km) south-west Carmarthen and 0.8 miles (1.3 km) north-east of the village of Llangain. Three miles to the north-west is Carmarthen Castle, and five miles to the south-west is Llansteffan Castle.