Blatec is a village in Semily District, in the Liberec Region, Czechia. Blatec lies at 380 m above sea level, 2.0 km from the Giant mountains. The nearest city is Jablonec nad Nisou, 21 km to the northwest. Among the landmarks around are Trosky Castle (3.8 km), Kost Castle (10.3 km) and Valdštejn Castle (5.8 km). Among the natural features are Zebín (14.0 km) and Postojna (6.1 km).