The municipality is located on a terrace on the northern slope of the Irchel elevation. It includes the village of Berg Gräslikon (which left Buch am Irchel in 1855 to join Berg). In 1619 Oberdorf left the municipality, in 1775 Schloss Schollenberg left and in 1788 Ziegelhütte left as well, all three joining Flaach.