lake district, northwestern Poland. Located immediately south of the Baltic coastal plain, the 20,000-square-mile (52,000-square-km) lakeland is bounded by the lower Oder River on the west, the ancient river valley occupied by the modern Warta and Noteć rivers on the south, and the lower Vistula River on the east.

Owing to the gentle descent of the land to the west as well as northward to the Baltic, the drainage pattern of the district is characterized by rivers that drain alternately from south to north and from east to west. As a result, a trellised, or grid, pattern of valleys dissects the region into rectangular blocks. The region abounds with marshes and streams and has considerably more than 1,000 lakes. Consequently, it is covered with sandy deposits consisting of postglacial outwash, morainal hills, and fluvial material.

The soil of the area is rather acidic and is deficient in humus. In the western part, brown forest soils have developed on the glacial till. In the eastern part, near the Vistula River delta, there are heavier and more fertile soils yielding rye, potatoes, and fodder crops. Important urban centres of the district are Szczecin, Piła, and Bydgoszcz.