upland region in Belarus. From northeastern Poland the ridge runs southeast into western Belarus and then swings northeast. Its total length is 320 miles (520 km). The ridge, covered by marine sands and clays, is in reality a series of separate uplands, of which the highest point is Dzerzhinskaya Mountain, at 1,132 feet (345 m), in the Minsk Upland. To the south of the ridge lie the extensive Pripet Marshes.