Jawatha Mosque (Arabic مسجد جواثا ) (also incorrectly spelled Al-Jawana) is located in the village of Al-Kilabiyah, about 12 km northeast of Hofuf, Al-Ahsa, Saudi Arabia. It was the earliest mosque built in east Arabia and most of the original structure is in ruins. The site is still used for prayer. Most of the mosque's original structure has been lost and it remains in danger of collapse. Only five small mud-brick arches remain. The visible ruins probably date from around the 9th century AD. The mosque's current structure's design is similar to the design of Masmak fort in Saudi Arabia.