Gleaston Castle is situated in a valley about 0.5 km north-east of the village of Gleaston, Cumbria, England. The castle is first mentioned specifically in 1389, although Sir John de Harrington, 2nd Baron Harington of Aldingham is said to have died at Gleaston in 1369. It is generally assumed that the castle was begun by his grandfather Sir John, 1st Baron Harington at around the time he was summoned to Parliament in 1326.