Kayakers enjoy a fall day on Nanjemoy Creek.
Nanjemoy Creek Kayakers enjoy a fall day on Nanjemoy Creek. © Alan Eckert Photography

Places We Protect

Nanjemoy Creek

Maryland / DC

One of Maryland's most pristine watersheds.

Check out an aerial photo of Nanjemoy Creek in Charles County and you’ll see why it has been called “the green thumb” of the Potomac River — about 80 percent of the land in the Nanjemoy watershed remains forested.

Relatively few roads carve through these woods, though human activities like residential development and incompatible forestry threaten this emerald-green oasis. The Nature Conservancy has embraced the challenge: retain the character of one of the state’s most pristine watersheds, where just eight percent of the land is currently protected.

The Conservancy has identified a project area of more than 48,000 acres offering the rare opportunity to save and restore this enormous block of contiguous forest. This remarkable situation exists, in part, because the landscape has not been fragmented as it has in other places — only about 150 private landowners own 25,106 acres (76 percent) of the unprotected land here.

Since establishing Nanjemoy Creek Preserve in 1978, The Nature Conservancy has worked to assemble the forest puzzle, helping conserve more than 3,510 acres to date (3,204 of which is the Conservancy's preserve).

Current Conservation at Work

  • Land acquisitions include a tract that was a missing slice from the core of the Conservancy’s conservation “pie,” adjacent to TNC land as well as protected state and federal land.  Sixteen interior-forest bird species find haven here, including five that are particularly sensitive to their surroundings. Wetlands provide breeding habitat for reptiles and amphibians.  This property is upstream from one of the two most viable populations of the dwarf wedge mussel in Maryland; protecting this section of forest will help maintain water quality for this vulnerable species. 

  • Another land acquisition of 275 acres is contiguous with 1,282 acres of protected state and federal lands, as well as 2,300 acres of TNC lands.
  • To protect our native forests, we have been controlling invasive Ailanthus trees that have been spreading throughout the preserve.

What You'll See

The preserve was established to protect a large breeding colony of great blue herons that once nested here.  The herons have since moved on, but the preserve abounds with life. 

Local farmer and naturalist Calvert R. Posey, site manager for many years, kept a detailed field journal listing 48 tree species, 86 wildflowers (including rare Virginia wild ginger), and numerous creatures — snakes, skinks and salamanders, to name a few. Posey noted that his lists on this richly endowed place were by no means complete.

TNC's ultimate goal is to protect a forested ecosystem large enough to function as nature intended it, and also large enough to encompass most, if not all, common and rare species. Raccoons, bobcats, skunks, and squirrels inhabit the woods; otters swim the creek; and the rare dwarf wedge mussel (found in only 20 sites worldwide) thrives in the sandy-mud bottom of stream banks. The deep forests here also attract many species of migratory songbirds.

Nanjemoy Creek
Visit one of Maryland's most pristine watersheds.

Nanjemoy Creek Enjoy one of Maryland's most pristine watersheds.

For more information about visiting Nanjemoy, contact Gabe Cahalan at 301-897-8570 or gcahalan@tnc.org.

Visit the Charles County Parks page to plan your visit and then download the audio tour map and driving directions (PDF). The letters marked on the map correspond to the audio files in the tour. 

Cell service may be unreliable at many of our preserves.  We recommend you download the recordings and maps before you visit.


Deborah Barber is Director of Land Management for the Maryland/D.C. chapter. She enjoys exploring nature both on her own and with others, especially her children, who often spot interesting things that adults miss. She enjoys cooking, traveling, gardening, and learning about geology.


A1: Introduction

A2: Boat launch point at Friendship Farm Park

A3: Trail head plants and Friendship Farm trails

B: Route 6 and Hancock Run Road

C: Nanjemoy Creek

D: Unnamed wetland

E: Purse State Park

F1: Chiles homesite

F2: Cal Posey Trail

G: Mallows Bay

The Nature Conservancy’s preserves are set aside to protect natural plant and animal communities. We invite you to observe and enjoy these preserves, but remember that every visitor has an impact. Please follow these guidelines to protect yourself and nature.

  • Preserves are open to the public during daylight hours. 
  • Passive recreation such as walking, bird watching, and photography is welcomed.  

The following activities are not allowed:

  • Bringing dogs onto the preserve.  Dogs are not permitted at any Conservancy preserve.
  • Picking flowers, mushrooms, etc.
  • Removing rocks or other parts of the landscape.
  • Smoking.
  • Camping, fires or cookouts.
  • Driving motorized vehicles, including ATV’s, except on designated access roads.
  • Biking.
  • Fishing, trapping, or hunting, except as otherwise posted.
  • Horseback riding.
  • Feeding wildlife.
  • Releasing animals or introducing plants.
  • Disposing of trash or other waste, including biodegradable materials.

To minimize your impact, we ask that you please also observe the following

  • Use trails.
  • Avoid walking in wet, boggy areas.
  • Inspect pant legs and shoes to remove seeds before entering and when leaving the preserve. Failure to do so could introduce unwanted weeds to new locations.
  • If you flush a ground nesting bird - stop and avoid walking near the nest area.
  • Observe all posted signs.
  • Please do not remove stakes, signs, flagging, tape or other objects - they might be part of a research project.
  • Please do not trespass on private property adjacent to the preserve.

For your own comfort and enjoyment, come prepared. Wear comfortable shoes for hiking, pack some rain gear and wear long pants with socks over them to protect yourself from ticks and poison ivy.

Bring along insect repellent and sunscreen for protection. Always remember to carry a water bottle for thirst quenching. And, of course, bring your binoculars, camera, field guide and a compass.

Tick and mosquito alert

When you get home, plan to drop your clothing directly in the laundry and do a tick check before you shower. Deer ticks, the type that carry lyme disease, are about the size of a pinhead and tend to attach in hair, under ears, underarms, trunk of the body, groin, and backs of the knees.

Remove them by gently pulling with tweezers and wipe the skin near the bite with a mild disinfectant. If, within 7-10 days after exposure, you experience a rash (especially an expanding "bull's eye" rash), chills, fever, headache, stiff neck, fatigue, swollen lymph nodes and/or aching joints and muscles, contact your doctor.

You can find more information on lyme disease at www.aldf.com or by calling the Centers for Disease Control and Prevention at (404) 332-4555.

More information

If you want to conduct research on a Nature Conservancy preserve, please share your plans with us and receive permission before starting. Contact Deborah Barber, Director of Land Management, at 301-897-8570 or dbarber@tnc.org.

If you observe any illegal activity on a preserve such as ATV use, do not confront the offenders yourself. However, do feel free to call local law enforcement.

Enjoy your visit and please report any problems with a preserve to the Maryland Chapter at 301-897-8570.

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