Mashhad, city, capital of Khorāsān-e Razavī ostān (province), northeastern Iran. It is located in the Kashaf River valley at an elevation of about 1,000 metres. As the burial place of ʿAlī al-Riḍā, the eighth imam in Twelver Shiʿism (Ithnā ʿAshariyyah), Mashhad is an important pilgrimage site.…