It occupies the site of the Roman-era city of Arethusa () and still contains some of its ancient ruins. It continued to exist as a relatively small, but strategic town throughout the early Islamic and Ottoman eras. Ar-Rastan is situated adjacently south of the large bridge linking Homs and Hama. The total land area of the town is 350 hectares. It is the site of the al-Rastan Dam, a major dam on the Orontes River that has a retaining capacity of 225 million m³. The dam is principally used for irrigation. The city also contains one of Syria's principal marlstone quarries.