About 5 percent of the area is permanent pasture. Less than 60 percent is in hardwood forests that are mainly in small to medium-size holdings and some larger tracts of state forests, game lands, and parks. Much of the prime farmland in the valleys is urbanized. Parallel sandstone and shale ridges are separated by narrow to moderately broad limestone and shale valleys. Average annual precipitation -900 to 1,275 mm.
Maximum precipitation is in spring and in summer, and the minimum is in fall.
About 525 to 650 mm falls during the growing season. The average annual snowfall is 60 to more than 130 cm. Water is plentiful in this area. Springs, wells, farm ponds, reservoirs, and streams are the principal sources of water. The major streams are the Susquehanna and Potomac Rivers.