Ferncliff Peninsula Natural Area is a 100-acre protected peninsula in Ohiopyle State Park near Ohiopyle, Pennsylvania, formed by a broad meander of the Youghiogheny River within the gorge. Its unusual setting supports many plants considered rare or unusual in Pennsylvania because the north-flowing river carries seeds from farther south and the gorge creates a warmer microclimate. Ferncliff is also an important example of late successional forest in the Allegheny Mountains. Its scientific value led to designation as a National Natural Landmark in 1973 and a State Park Natural Area in 1992 to prevent further development and preserve its ecology. A two-mile loop trail also passes prehistoric plant fossils near Ohiopyle Falls.