This region is the most densely populated and least forested of all the regions. It is, however, amazingly diverse in its wildlife resources. At the southeast corner is a strip of coastal plain with remnants of tidal and freshwater wetlands. The riparian forests along the region's rivers are some of the most important eagle habitat in the state.
At the west end, the Susquehanna River flows from north to south creating an ideal route for migrating birds and abundant food and shelter for resident birds. The Delaware River runs the length of the region's eastern border and the state line. Since it flows unimpeded by dams, the Delaware River is home to American eels and shad and other fish that link Pennsylvania with the ocean. This enhances the diet of eagles and other piscivorous birds in the drainage.
To the north, several parallel ridges of the Appalachians run east and west; the Blue Mountain extends across the whole region. Between the ridges in Dauphin County, Fishing, Stony and Clark creeks run through the valleys. The Schuylkill and Lehigh rivers make their way across the region as well before emptying into the Delaware. Old canals also follow these valleys and provide opportunities for visiting riparian areas at these historic sites.
Throughout the region many man-made reservoirs enhance the abundance and variety of wildlife.