 Until 2010, Alt St. Johann was a municipality in the Toggenburg constituency, consisting of the villages of Alt St. Johann and Unterwasser and the hamlet of Starkenbach on the valley floor.Higher up in the valley are scattered settlements on the valley sides as well as seasonal alpine settlements on the northern slope of the Churfirsten and into the Alpstein sub-range of the Appenzell Alps.Alt St. Johann has a population () of 1466. , about 9.4% of the population was made up of foreign nationals.