Abdullah ibn Umar Mosque is one of the historical mosques in Kermanshah province, located in Dalahu County and the city of Rijab. Researchers attribute the construction of this mosque to Abdullah ibn Umar. Unlike all Islamic mosques, the mihrab of the mosque does not protrude from the southern wall, but has been added to the mosque wall by working stucco and is completely distinct from the wall.
This mosque is located in the middle of the old village of Rijab (Rijab Bala). The building of this mosque is rectangular in shape, made of stone and mortar. This building was one of the pre-Islamic structures that was converted into a mosque during the Islamic era.
The minaret of the mosque was built on the roof of the mosque in the southwest corner many years after the construction of the mosque. The architectural style of the minaret resembles mostly Towers of Silence (Dakhma), especially the Rijab Tower of Silence. The mosque pulpit is built behind the mihrab that is made of stone and plaster with five steps.
This mosque was restored by the Cultural Heritage Organization in 1991 and was registered as one of Iran's national monuments with the registration number 21797, on June 7, 2006.