The patron saint of Saint-Marcel is Saint Marcellus, celebrated on 16 January. The parish church dedicated to him, on a small promontory, holds a fine 18th-century high altar and has been rebuilt several times after being destroyed by floods of the Dora Baltea river.
The territory of Saint-Marcel has been inhabited since prehistoric times: at Seissogne and Réan numerous rock engravings have been found, including cup marks and anthropomorphic drawings, while at Tsampic in 1990 a Bronze or Iron Age hillfort was discovered. At Surpian stands instead the castle of Saint-Marcel, well preserved and currently under restoration.
