Suostas is a village in Biržai District Municipality, in Panevėžys County, Lithuania. Suostas lies at 51 m above sea level. It has 78 inhabitants (2021). The nearest city is Panevėžys, 69 km to the southwest. Near the border: Latvia, 5.8 km. Among the landmarks around are Church of the Assumption of Mary in Skaistkalne (7.3 km), Rundāle Palace (43 km) and Biržai Castle (14.2 km). Among the natural features are Cow cave (13.3 km) and Jurgis Bielinis oak (1.1 km).