Bagillt, a town of Flintshire, North Wales, 14½ m. from Chester, on the London & North Western railway, in the ancient parish of Holywell. Pop. (1901) 2637. Its importance is due to its zinc, lead, iron, alkali and kindred works, and its collieries. Above Bagillt is Bryn Dychwelwch, "Hill of Retreat," so called from the retreat effected by Owen Gwynedd, when pursued by Henry II., with superior numbers. Near is Mostyn Hall, dating from the time of Henry VI., the seat of one of the oldest Welsh families. Here are antiquities and MSS. (old British history and Welsh, brought from Gloddaeth), a harp dated 1568, torques (torchau), etc. Henry VII., then earl of Richmond, is said to have been concealed here in the reign of Richard III., when the lord of Mostyn was Richard ap Howel.