(1929) Kirchberg has an area, , of . Of this area, 59.5% is used for agricultural purposes, while 30.9% is forested. Of the rest of the land, 9% is settled (buildings or roads) and the remainder (0.6%) is non-productive (rivers or lakes). The municipality is located in the Toggenburg
Wahlkreis. It is the most north-western municipality in the
Wahlkreis and in bordered in the west by canton
Thurgau and in the east by the
Thur river. It consists of the village of Kirchberg on a high plateau in the center of the municipality, the village of Gähwil south of Kirchberg and the
linear village of
Bazenheid on a terrace above the Thur. Additionally, scattered around the municipality, there are the
hamlets of Müselbach, Dietschwil, Ötwil, Nuetenwil, Rupperswil, Bräägg, Schalkhusen, Wolfikon, Lütenriet, Buomberg, Bäbikon and Husen. ==Coat of arms==