Çayüstü is a neighborhood in Bigadiç District, in Balıkesir Province, Türkiye. Çayüstü lies at 282 m above sea level, 0.7 km from the Anatolian plateau mountains. It has 389 inhabitants. The nearest city is Balıkesir, 30 km to the north. Among the landmarks around are İkizcetepeler Dam (11.5 km), Germe (25 km) and Çamköy Dam (18.0 km).