Turnov is a town (město) in Semily District, in the Liberec Region, Czechia. Turnov lies at 260 m above sea level, 4.8 km from the Giant mountains, by the Jizera. It has 14,577 inhabitants (2024). The nearest city is Jablonec nad Nisou, 16.0 km to the north. Among the landmarks around are Kost Castle (10.5 km), Trosky Castle (9.4 km) and Valdštejn Castle (2.6 km). Among the natural features are Maškova zahrada (0.1 km) and Postojna (4.4 km).