Sergen is a village in Vize District, in Kırklareli Province, Türkiye. Sergen lies 0.0 km from the Strandzha mountains. It has 1,102 inhabitants (2022). The nearest city is Saray, 34 km to the southeast. Near the border: Bulgaria, 25 km. Among the landmarks around are Sergen Mosque (0.1 km), Gazi Süleyman Paşa Mosque (15.3 km) and One Arched Fountain (6.1 km). Among the natural features are Dupnisa Cave (21 km) and Yenesu Cave (22 km).