Rorschach is a city in the canton of St. Gallen, Switzerland, on Lake Constance. As of 2003 it had a population of 9000 (approx.) and a surface of 1.78 km².
The place was first mentioned in 850 as Rorscahun. In 947, Otto I granted the abbot of St. Gall the right for markets, coinage and tariffs at Rorschach.
Sights include the Kornhaus, lake promenade, aviation museum in Altenrhein, the abbey Mariaberg, as well as the St. Anna, Wartensee, Sulzberg and Wartegg castles.