Kildavnet Castle is a historic structure located on Achill Island in County Mayo, Ireland. Built in the 15th century, it served as a stronghold for the O'Malley clan, a prominent family in the region. The castle is situated near the coast, offering strategic views of the surrounding landscape and sea. The castle features a rectangular layout with thick stone walls and a central courtyard. Although it is now in ruins, Kildavnet Castle remains a popular site for visitors interested in Irish history and medieval architecture. Its picturesque setting and historical significance make it a notable landmark on Achill Island.