4 Eylül is a neighborhood in Bigadiç District, in Balıkesir Province, Türkiye. 4 Eylül lies in the Alaçam Dağları mountains. It has 1,663 inhabitants. The nearest city is Paşa Alanı, 36 km to the northwest. Among the landmarks around are Çamköy Dam (9.7 km), Çaygören Dam (14.5 km) and İkizcetepeler Dam (20 km).