Nature reserve in Pensylvania on which Fallling Water is located A nature reserve is an area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research. ... State nickname: The Keystone State Other U.S. States Capital Harrisburg Largest city Philadelphia Governor Ed Rendell Official languages None Area 119,283 km² (33rd) - Land 116,074 km² - Water 3,208 km² (2. ...