This mountain area extends some 125 kilometers along the present southwest borders of the Czech Republic, Austria, and Germany. For the most part, the area is forested. The highest point is Plechý, a mountain measuring 1378 metres. Characteristic of the Šumava are its uplands inlaid with numerous marshes. The mountains are a natural reservoir of underground water. The Vltava river originates here.
   The main part of the Šumava region lies within the Vltava river basin area in the Western part, and the remainder in the Otava and Úhlava river basins. The Danube river basin is secondary. The main Šumava river, the Vltava, has a umber of tributaries in its upper part into which the surrounding marshes drain.
   There are several splendid lakes in the area, each bearing its individual character. Some of these are the Plešné, Prášilské, Černé, and Čertovo lakes. The atmosphere of Šumava is complemented by numerous small, tranquil ponds which interlace the marshes. Černé jezero (Black Lake). The largest natural lake in Šumava is of glacial origin. It is situated amongst forests on the slope of Jezerní mountain, 1008 m. above sea level. The area of the lake is 1847 hectares.