Whites Castle, Medieval castle in Athy, Ireland

White's Castle is a three-storey tower house with a battered base on the east bank of the River Barrow in Athy, County Kildare, overlooking Crom Abú Bridge. It was built around 1575 on the site of a 1417 Norman tower house, and a three-storey rectangular extension was added to the north end between 1795 and 1802. The line of the original west wall is visible around the halfway point of the current wall, and sash windows were added in 1872.

A Norman tower house was built here in 1417 by John Talbot, 1st Earl of Shrewsbury and King's Lieutenant, to protect the new bridge over the River Barrow. By 1505 it was derelict and Gerald FitzGerald, 8th Earl of Kildare, was asked to rebuild it; the fortified house was completed around 1575. It changed hands repeatedly during the Irish Confederate Wars, was a notorious gaol by 1730, and later served as a prison for rebels after 1798 and as a police barracks.

On the right of the main doorway is a stone coat of arms of the Earl of Kildare, marking the FitzGeralds' claim to the castle. On the left side of the original doorway, Richard Coosen, Sovereign of Athy, added a crucifixion plaque in 1573, bearing his name and the date. The bridge outside is Crom Abú Bridge, named after the war cry of the FitzGerald family.

The castle stands right on the riverbank and is easy to reach on foot from Athy town center. The building is privately occupied, so the interior is generally not open to visitors, but the exterior can be viewed from the riverside path.

The southern section of the tower still has original punch-dressed stones visible around several window openings, a type of finish where the stone surface is worked with a pointed tool to create a rough, textured look. This technique was common in the 15th century but is rarely seen in such good condition today.