The municipality of Mörschwil is located in the canton of St. Gallen at around 550 m above sea level and belongs to the electoral district of Rorschach. First mentioned in 811 under the name "Maurini vilare", the village is nestled between the neighboring municipalities Berg, Steinach, Tübach, Goldach, Untereggen, St. Gallen and Wittenbach. It is bordered by the two small rivers "Goldach" and "Steinach". 

The municipal area is spread over 9.84 km2 and is characterized by many small hamlets (e.g. Oberbüel, Aachen, Näppenschwil, etc.). As at December 31, 2024 there were 3,632 registered residents, 326 of whom were foreign nationals.

With a tax rate of 70%, Mörschwil is one of the most tax-efficient municipalities in the canton of St. Gallen.