Places We Protect

Eales Preserve at Moosic Mountain


Colorful shrubs surround a rocky landscape. Low, bright red bushes grow in between the flat gray rocks of an open plateau. The tops of trees leafed out in bright orange line the background.
Moosic Mountain Barrens Autumn in the barrens at the Dick and Nancy Eales Preserve at Moosic Mountain. © George C. Gress/TNC

Easily accessible from Harrisburg, Philadelphia and New York City, Moosic Mountain is packed with outdoor opportunities.

Please Note: The O'Conner Reservoir was drained and the dam was breached in December 2021. The previous reservoir area immediately surrounding the dam is sensitive to disturbance until the vegetation becomes re-established; the area will remain closed to visitation until further notice. Additional signage has been posted, informing accidental visitors to please stay off the dam.



The Dick & Nancy Eales Preserve at Moosic Mountain provides sweeping views of Pennsylvania’s northeastern corner and represents one of the best locations in the northeastern U.S. for ridge-top heath barrens.

Contrary to its name, the Moosic Mountain “barrens” comprise a healthy mosaic of stunted pine and oak forest dominated by huckleberry, blueberry, rhodora and other low-lying shrubs that attract a broad array of birds, butterflies and moths—including the globally rare sallow moth and barrens buckmoth.

In 2001, TNC purchased 1,200 acres in the heart of Moosic Mountain that were slated for development, protecting sensitive mountaintop habitat and reducing impacts to water quality.

In 2009, TNC named the preserve after Dick and Nancy Eales, whose generosity has enabled us to continue to expand the preserve, which today encompasses about 2,250 acres, and to conduct the robust prescribed burning necessary to maintain the fire-dependent natural community.




Daily, from dawn to dusk


Hiking, hunting (in cooperation with Pennsylvania Game Commission regulations), birding and biking.


2,250 acres. The number grows to approximately 15,000 acres when the preserve is combined with adjacent protected lands owned by the Pennsylvania State Game Commission and the Pennsylvania Bureau of Forestry.

Explore our work in Pennsylvania

Moosic Mountain

TNC works with state government and local partners to foster compatible uses and a sense of ownership among bird watchers, mountain bikers, sportsmen and other community groups interested in protecting Moosic Mountain’s ecological resources.

Low shrubs with brilliant red leaves dominate the foreground, obscuring the view of a narrow foot path that curves behind them into the woods.
A person wearing a yellow shirt and blue helmet navigates a mountain bike over rocky terrain following a line of short trees.
A cluster of bright pink flowers with thin curving petals bloom at the end of a thin branch.
Two dozen people wearing yellow fire gear pose together in a group in an open field at the end of a controlled burn.
White cup shaped flowers with pink edges bloom on a green leafed bush.


  • The preserve boasts one of the best and largest ridge-top heath barrens in Pennsylvania. Color abounds in spring and fall. Look for painted trillium (Trillium undulatum) in late spring on the forested ridges. This low plant has a small white flower with a crimson heart nestled in the center of three dark-green leaves. 

    Moosic Mountain also harbors an array of birds, butterflies and moths—including the globally-rare sallow moth and barrens buckmoth (Hemileuca maia maia). You'll see the moth with its distinctive black bands only when it emerges from underground pupae in the fall. Throughout the spring and early summer, its showy larvae, a spiny black and yellow caterpillar with irritating spines that look like neon anemones, feed almost exclusively on scrub oaks. 

    Visit the preserve during spring to witness songbird migration. Documented breeding birds at Eales include prairie warbler, black-and-white warbler, chestnut-sided warbler, hermit thrush, northern harrier and broad-winged hawk. 

    The small, zebra-striped songbird black and white warbler (Mniotilta varia) breeds in Pennsylvania's forests each summer and spends its winters as far south as Colombia and Venezuela. You may see it creeping along branches searching for insects, but are more likely to hear its very high-pitched two­note song, which some describe as a squeaky wheel. 

    With its flute-like song, the hermit thrush (Catharus guttatus) has been lauded by Walt Whitman and is, to many, the voice of Moosic Mountain. The hermit thrush breeds and forages for insects and berries in northeast Pennsylvania's forests after a long journey from its wintering grounds in the southern United States and south to Central America. 

    The northern harrier hawk (Circus cyaneus) can often be seen gliding on the thermals, currents that flow across the mountain ridges. Its feathers are streaky brown, but this low-flying hunter is most recognizable by its long tail, white rump and slightly rounded wings. 

    Game species such as white tail deer, black bear, turkey, ruffed grouse, snowshoe hare and coyote can also be found at the preserve.

    Ruffed grouse (Bonasa umbellus) is Pennsylvania's state bird. At the peak of the spring mating season, at dawn, you might see a male fanning his tail and drumming-beating the air with his wings to attract a female. Some say it sounds like a car engine starting up. 

    Whether wearing its tawny summer coat or pure white winter fur, the snowshoe hare (Lepus americanus) can be recognized by the black tips of its ears. The Central Appalachians mark the southern end of the hare's range, so its large, furry feet equip it well for the snowiest of Pocono winters. 

    Contact TNC’s Hauser Nature Center in Long Pond for information about hunting on or near the preserve.

  • We are creating a community science database of all kinds of life—from lichens to ants, mushrooms to plants, birds to mammals and everything in between for our preserves in Pennsylvania and Delaware.

    TNC's roots began with local citizens and scientists concerned about special places and species. That legacy continues today. Across our lands, we are utilizing iNaturalist—a digital platform that gives users an opportunity to share and discuss their findings.

    Of our 14 preserve projects in iNaturalist, nine have observations recorded; help us increase that number and our understanding of the species—good and bad, native as well as invasive—that can be found on TNC lands across the state. This information can also help guide and inform our conservation staff's management and monitoring decisions.

  • While visiting Eales Preserve please DO:

    • Take precautions against ticks, mosquitoes, chiggers and sunburn.
    • Wear sturdy footwear.
    • Tuck pant legs into socks/shoes.
    • Apply insect repellant and sun protection.
    • Bring drinking water.
    • Watch for poison ivy.
    • Stay on marked trails.
    • Remove all litter. 
    • Enjoy nature!

    DO NOT:

    • Feed or disturb wildlife.
    • Release animals or introduce plants.
    • Trap, fish, dig, pick or remove plants or other artifacts from the preserve.
    • Bring motorized vehicles, ATVs, bicycles or horses.
    • Bring alcohol.
    • Camp (NO fires allowed!)
    • Smoke.
    • Swim in the pond.
A man using a motorized wheelchair enters a preserve.

Connect with Nature

Improving Accessibility

In early 2021, avid outdoorsman Scott Wilson set out to visit Eales Preserve—a place he has enjoyed many times over the years—but came up against an obstacle right at the start. An entrance gate installed to deter ATV use on the preserve was making it impassable for people who use wheelchairs or similar mobility equipment. So, Scott—who now uses a wheelchair and is a member of the organization Individual Abilities in Motion (I AM)—reached out to TNC’s Pennsylvania team to see if changes could be made.

That first contact kicked off a working relationship between the two groups to look at how accessibility could be improved at local TNC preserves, with Scott and others from I AM providing firsthand feedback. The first of those changes is a new gate at the Eales preserve that allows wheelchairs, recumbent hand bikes and other mobility equipment to access the trailhead.

“Making places like nature preserves accessible opens up a lot of opportunities for people. It’s important to improve accessibility wherever we can to allow the broadest range of individuals to experience what nature has to offer,” says I AM president Joe Salva. “Just because an individual has a mobility impairment does not mean that they have less desire to enjoy the same places as everyone else does and experience all the beauty this area has to offer.”

I AM focuses on helping people with mobility impairments celebrate and develop their personal abilities so they can more fully engage with the world, making them a perfect partner in making TNC preserves in Pennsylvania and Delaware more accessible for all.

O’Conner Reservoir Dam

Removal and Restoration

The O’Conner Reservoir dam has been regularly monitored by TNC and the State of Pennsylvania since TNC established Eales Preserve at Moosic Mountain in 2001. Signs of erosion and water moving through the dam were noted in 2020, requiring immediate short-term repairs and necessitated the lowering of water levels in the reservoir—a difficult and time-consuming task for our stewardship staff.

After three tropical storms passed through northeast Pennsylvania in the summer of 2021, it became apparent that the removal of the 128-year-old O’Conner Reservoir dam was necessary to address safety and liability issues. The breach of O’Conner dam occurred in December 2021 and was authorized under emergency permit provisions.

When TNC acquires a parcel of land, we commit—both legally and ethically—to steward that land in perpetuity. TNC often acquires land that includes legacy infrastructure like homes, barns, bridges or dams. For TNC preserves that are open for recreation, public safety is the top stewardship priority.

With the design, permitting and construction phases of the project completed this past winter, our freshwater conservation team has now turned its attention to restoration. The dam removal has created an opportunity to restore the original stream channel and floodplain at the bottom of the reservoir, which will create a more natural headwater habitat for Sterry Creek.

A narrow channel of water curves along what was the bottom of the O'Connor Reservoir. In the background heavy construction equipment widens the breach in the earthen dam.
Looking across the rippled surface of a large reservoir lake. An earthen dam is just visible in the background forming a line in front of a stand of trees.
Before and After The O'Conner Reservoir in November 2019 and following the breach of the dam in December 2021.

The stream channel is being allowed to form naturally through the previous reservoir area while the stream section running through the dam breach is designed to accommodate higher streamflows. The rock and soil material removed from the breach was placed on the upstream and downstream sides of the remaining intact sections of dam.

Visitors will be able to see the juxtaposition of our past and our future, as portions of the dam—including the stoned lined spillway—remain intact, and pieces of the timber crib encountered during construction are on display allowing for historic interpretation of the original dam and its construction.

Ecological benefits will continue to increase over time, as native vegetation becomes re-established in the former reservoir area, improvements in riverine, wetland, and riparian habitats occur and the movement of species between headwater and downstream reaches are restored.

Over the coming months, TNC will evaluate the necessity of further restoration efforts that enhance the ecological communities, wildlife and recreational assets of the preserve.

Quote: Christine Arnott

Seeing the original stream channel emerge once again from the bottom of the reservoir reminded us how resilient nature can be. The former dam site will provide a great opportunity for us to observe how nature can restore itself.

Freshwater Project Manager, The Nature Conservancy in PA/DE

Removal and Restoration

In the summer of 2021, it became apparent that the removal of the 128-year-old O’Conner Reservoir dam was necessary to address safety and liability issues. The breach of O’Conner dam occurred in December 2021.

Four people use 10 gallon buckets to bail water into a PVC piping set up to drain the large reservoir behind them.
Exposed rock face of a dam spillway. Roughly shaped blocks of stone create a tall wall that extends and disappears into a stand of trees.
A large yellow backhoe sits on top of an earthen dam. The large breach in the dam reveals the stone that faces the back side of the dam. A few inches of water remain in the reservoir.
A large yellow backhoe sits on top of an earthen dam. A large breach has been opened in the area in front of the machine. The bucket is full of dirt and rocks.
A backhoe unloads dirt into the back of a dump truck. The heavy equipment sits at the top of an earthen dam that is being breached. Water cascades into a pool at the foot of the dam.

Help Support Our Work

By making an unrestricted gift to the PA/DE chapter, your money will go towards our highest priority needs related to this critical project. We want to honor your wishes for how your gifts are used. If you wish to designate your gift toward a specific aspect of the O'Conner dam removal and stream restoration project, please contact PA/DE Deputy Executive Director Donna Bowers at

Stay in Touch

Subscribe to Nature News, our monthly e-newsletter. Get the latest news and updates about our conservation efforts locally and around the world, delivered straight to your inbox.

Find More Places We Protect

The Nature Conservancy owns nearly 1,500 preserves covering more than 2.5 million acres across all 50 states. These lands protect wildlife and natural systems, serve as living laboratories for innovative science and connect people to the natural world.

See the Complete Map