Fussach (also written Fußach) is a municipality in the district of Bregenz, in the Austrian state of Vorarlberg. It lies in Austria's westernmost region, on the eastern shore of Lake Constance (Bodensee), near the point where the Rhine flows into the lake.
The area is part of the Rhine delta on Lake Constance, a landscape shaped by the river's sediment deposits and by the lake's fluctuating water levels. Fussach sits close to the neighbouring communities of Hard and Höchst, and to the German border just across the Rhine, which places it within the wider Bodensee region shared by Austria, Germany and Switzerland.
As a municipality of the Bregenz district, Fussach is one of the smaller settlements in Vorarlberg's lowland belt along the lake. Its position on the lake and the Rhine delta has historically tied it to fishing, water management and transport along the Bodensee.