Ajlun Castle, Islamic fortress in Ajloun, Jordan

Ajlun Castle is a stone fortress on the crest of Jabal Auf at 1,023 metres, built as a semi-square with four corner towers, each of two storeys. Its thick walls are pierced by arrow slits, and a moat 16 metres wide and 12–15 metres deep surrounds it. Aibak ibn Abdullah added a southeastern tower and the gate in 1214–1215.

Izz al-Din Usama, a general in Saladin's army, built the castle in 1184 to control the Bedouin tribes of Jabal Auf and block Crusader incursions from Belvoir and Karak. In 1214–1215 the Mamluk governor Aibak ibn Abdullah added a southeastern tower and the gate. The Mongols damaged it in 1260, and Sultan Baibars restored it soon after.

The fortress served as a vital checkpoint for controlling trade routes and iron mines in the region. Visitors can observe how the structure was integrated into the landscape to monitor the valleys and the Jordan Valley below.

The site is easily accessible from Ajloun town and located on an elevated hilltop with expansive views. Visitors should wear comfortable walking shoes and be prepared for the terrain when exploring the towers and courtyards.

The castle's moat, cut into the rock, averages 16 metres wide and 12 to 15 metres deep; it served both as a barrier and as a reservoir collecting rainwater. Inside, vaulted halls that housed Ayyubid soldiers and their horses stand beside wells meant to hold thousands of cubic metres of rainwater. The mortar mixed lime with copper, which oxidises and changes colour where damp seeps in, so restorers use it to spot leaks.