About 84% of Hungary is below 200 m (656 ft) in altitude, its lowest point, at the Tisza River, being 78 m (256 ft) above sea level and the highest being Mt. Kékes (1,014 m/3,327 ft) in the Mátra Mountains, northeast of Budapest. The country has four chief geographic regions: Transdanubia (Dunántúl), the Great Plain (Alföld), the Little Plain (Kisalföld), and the Northern Mountains. Hungary's river valleys and its highest mountains are in the northeast. Generally, the soil is fertile. The chief rivers are the Danube (Duna) and Tisza. The largest lake is Balaton, which has an area of 601 sq km (232 sq mi).