Poland's average altitude is 173 m (568 ft); 75.4% of the land is less than 200 m (656 ft) above sea level. The highest point, Mount Rysy (2,499 m/8,199 ft), is located in the Tatra Mountains on the Slovakian border. The principal topographic regions are an undulating central lowland with a crystalline platform and warped bedrock; the Baltic highland in the north, a glaciated region with many lakes and sandy soils; and the coastland, a narrow lowland with promontories, bays, and lakes. The southern uplands are marked by rich loam and mineral deposits.
Several important navigable rivers drain into the Baltic Sea, among them the Vistula (Wisla), the Oder, the Bug, and the Warta. There are over 6,000 lakes in the northern lake region. Good harbors have been developed on the Baltic Sea.