From List of National Natural Landmarks, these are the National Natural Landmarks in Pennsylvania. There are 27 in total.
| Name | Image | Date | Location | County | Ownership | Description | |
|---|---|---|---|---|---|---|---|
| 1 | Bear Meadows Natural Area | 1965 | 40.4061°N -77.1739°W | public/state Rothrock State Forest | |||
| 2 | Box Huckleberry Site | 40.4061°N -77.1739°W | public/state Tuscarora State Forest | A 10acres natural area which preserves a rare colony of box huckleberry over 1,000 years old. | |||
| 3 | Cook Forest State Park | 41.3236°N -79.1639°W | public/state | A 8500acres state park notable for its spectacular stands of old-growth Eastern White Pine and Eastern Hemlock, many from around 1644. | |||
| 4 | Ferncliff Peninsula Natural Area | 1973 | 39.8676°N -79.4982°W | public/state Ohiopyle State Park | This 100acres peninsula is formed by a meander in the Youghiogheny River. It is a good example of a late successional forests in the Allegheny Mountains | ||
| 5 | Ferncliff Wildflower and Wildlife Preserve | 1972 | 39.7826°N -76.2427°W | private/nonprofit | The vegetation within the Ferncliff Wildflower and Wildlife Preserve is an excellent example of a mixed mesophytic forest that occupies the valleys and ravines of the oak-chestnut forest region. | ||
| 6 | Florence Jones Reineman Wildlife Sanctuary | 1973 | 40.2667°N -77.2667°W | private/family trust | Contains a 3100acres diverse ecological community. | ||
| 7 | 1968 | 41.2717°N -77.3269°W | Tioga Lycoming | public/state Tioga State Forest | Known as the "Grand Canyon of Pennsylvania", a deep gorge carved by glacial meltwater. The maximum depth of the canyon is 1,450 feet (442 m) at Waterville, near the southern end. At Leonard Harrison and Colton Point State Parks, the depth is more than 800 feet and from rim to rim is approximately 4,000 feet (1200 m). Protects 160000acres. | ||
| 8 | Hawk Mountain Sanctuary | 1965 | 40.6408°N -75.9922°W | Berks Schuylkill | private/nonprofit | A sanctuary on a Blue Mountain ridge, known as an excellent vantage point for hawk migrations. | |
| 9 | 1973[1] or 1977[2] | 41.691°N -79.254°W | Warren | public/federal Allegheny National Forest | An old-growth white pine forest of 120acres. | ||
| 10 | 1972 | 40.2384°N -77.6414°W | Perry | public/state Tuscarora State Forest | Features numerous old growth hemlock trees. | ||
| 11 | 1967 | 41.0361°N -75.6839°W | public/state Hickory Run State Park | A 16.5acres landscape of sandstone boulders, which were formed approximately 20,000 years ago. | |||
| 12 | Lake Lacawac | 1968 | 41.3823°N -75.2921°W | private/nonprofit | A 52acres glacial lake surrounded by a hardwood conifer forest. | ||
| 13 | McConnells Mill State Park | 1972 | 40.9267°N -80.19°W | Lawrence | public/state | Protects 2546acres of the Slippery Rock Creek gorge, including several waterfalls. | |
| 14 | Monroe Border Fault | 1980 | 40.5798°N -75.1976°W | Bucks | public/state Nockamixon State Park | An upland along the Delaware River, the area features a variety of exposed rocks from different geological ages. | |
| 15 | Nay Aug Park Gorge and Waterfall | 1989 | 41.4014°N -75.6428°W | public/municipal | Located in an urban park, it features a rock-strewn, heavily wooded gorge. | ||
| 16 | Nottingham Park Serpentine Barrens | 2009 | 39.7405°N -76.0391°W | Chester | private/nonprofit | A 651acres county park on one of the largest outcrops of serpentine in the eastern US, which creates a savanna-like habitat with a number of unusual flora. | |
| 17 | Presque Isle State Park | 1967 | 42.1631°N -80.1008°W | public/state | A 3112acres sandy peninsula stretching into Lake Erie. | ||
| 18 | Reynolds Spring and Algerine Swamp Bogs | 1974 | 41.5509°N -77.4975°W | Tioga Lycoming | public/state Tioga State Forest | Contains two bogs of 1302acres and 84acres, which are surrounded by thick oak and pine groves. | |
| 19 | The Glens Natural Area | 1968 | 41.3261°N -76.2794°W | public/state Ricketts Glen State Park | 2845acres of old growth forest, with many trees exceed 100feet in height. Twenty two separate named waterfalls are located in the area. | ||
| 20 | Snyder Middleswarth Natural Area | 1967 | 40.81°N -77.2831°W | public/state Bald Eagle State Forest | A hemlock, pine, and oak forest located on 500acres. | ||
| 21 | Susquehanna Water Gaps | 1968 | 40.5209°N -76.9789°W | Cumberland, Dauphin, Perry | public/state | Millions of years of erosive rock create impressive landforms of unique geologic heritage and outstanding natural beauty, as the Susquehanna River cuts through five ridges of the Appalachian Mountains north of Harrisburg. | |
| 22 | Tamarack Swamp | 1977 | 41.989°N -79.555°W | public/state | An acidic kettle pond bog. | ||
| 23 | Tannersville Cranberry Bog | 1974 | 41.04°N -75.306°W | private/nonprofit | A 1000acres kettle lake fen. | ||
| 24 | John Heinz National Wildlife Refuge at Tinicum | 1965 | 39.8859°N -75.2624°W | Philadelphia Delaware | public/federal | Protects a tidal marsh of 350acres located in an urban environment. | |
| 25 | Tionesta Scenic and Research Natural Areas | 1973 | 41.645°N -78.941°W | Warren McKean | public/federal Allegheny National Forest | 4131acres of old growth forest on the Allegheny Plateau. | |
| 26 | 1977 | 41.9434°N -79.7631°W | private/nonprofit | A peatland of 125acres located near the shore of Lake Erie. | |||
| 27 | Wissahickon Valley | 1964 | 40.0161°N -75.2057°W | Montgomery, Philadelphia | public/state Fort Washington State Park | Protects an urbanized tributary of the Schuylkill River, which features a gorge and thick woodlands. | |