Trisobbio is a comune (municipality) in the Province of Alessandria in the Italian region Piedmont, located about 80 kilometres (50 mi) southeast of Turin and about 30 kilometres (19 mi) south of Alessandria.
Trisobbio borders the following municipalities: Carpeneto, Cremolino, Montaldo Bormida, Morsasco, Orsara Bormida, Ovada, and Rocca Grimalda.
- Castle, existing from as early as the 13th century
- Parish church of Nostra Signora Assunta, known from the late 14th century
- Communal Palace, of medieval origins
- ^ All demographics and other statistics: Italian statistical institute Istat.