Islands of the Potomac Wildlife Management Area

Mason IslandLocated on the Potomac River in Garrett, Allegany, Washington, Frederick, and Montgomery Counties are 30 islands that have been designated as the Islands of the Potomac WMA. Of these Islands, three are open to public hunting in Montgomery County. These are Oxley Island, Mason Island, and Maddox Island.

Maddux Island is located near Poolesville, MD. It is seated between Seldon Island and Tenfoot Island (both privately owned) about 2 miles downstream from Whites Ferry. It was purchased in 1970 by the Maryland Department of Natural Resources. This 169 acre island is adjacent to McKee-Beshers WMA and may also be known as Van Deventer Island.

Oxley Island is located near Dickerson, MD, one mile north of Whites Ferry. It was purchased in 1993 by the Maryland Department of Natural Resources. This island is approximately 30 acres and is just upstream from Mason Island.

Mason Island is also near Dickerson, MD, about one mile north of Whites Ferry. It was purchased by the Maryland DNR in 2015. This island is 275 acres and is just down river from Oxley Island.

The Islands of the Potomac WMA is only accessible by water. See Maryland’s Online Water Access Guide for information on boat ramps.

Oxley and Mason Islands Map

McKee-Beshers and Maddux Island Map​

Regulations for All Users

Unless otherwise posted or with a permit issued by the Service it is UNLAWFUL to:

  • Operate or possess a vehicle on roads, trails, or waterways not open to general traffic.
  • Bait or feed wildlife.
  • Use or construct permanent blinds or tree stands. All portable blinds or stands must be removed at the end of the day.
  • Ignite, cause to be ignited, or maintain a fire.
  • Camp
  • Remove, disturb, damage, or destroy any mineral, plant, rock, tree, or nongame animal.
  • Have dogs off leash from April 15 through August 15.
  • Use dogs to chase fox and raccoons.
  • Release any animal or plant.
  • Conduct commercial activities.
  • Place a cache for the purpose of geocaching.
  • Operate, possess, or use combustibles, explosives, or fireworks.
  • Dig for relics and treasures, remove prehistoric or historic artifacts, or use a metal detector without a permit from the Office of Archeology.
  • Deposit litter or refuse including, but not limited to, animal carcasses, appliances, brush, debris, furniture, garbage, hazardous material, tires, waste paper, yard waste, or other litter.
  • Vandalize real property including any blind, building, crop, equipment, gate, habitat, plant, road, sign, trail, vehicle, vessel, or other public property.
  • Graze cattle, goats, horses, sheep, or other domestic animals.
  • Place decoys prior to 1 hour before legal shooting hours, leave decoys overnight, or remove decoys later than 1 hour after legal shooting hours.​
  • Target shoot​.


Public hunting on Maddox, Mason, and Oxley Islands is permitted during legal hunting seasons. No permits or reservations are required. Hunting is available for all legal game species in accordance with current hunting laws and regulations established by the Maryland Department of Natural Resources.

  • Hunting is permitted Monday through Saturday. No hunting is allowed on Sundays.
  • Permitted hunting devices include all legal devices allowed in Montgomery County.
  • Trapping is allowed by permit only. Contact the Gwynnbrook Wildlife Office at 410-356-9272 for more information.
  • No public hunting or trapping is allowed on any islands in Montgomery County besides Mason, Oxley, and Maddux.

Non-Hunting Users

The Islands of the Potomac WMA is open year-round to non-hunters. No permit or reservation is needed. Be aware of active hunting seasons. The property is open for the following activities:


  • Hiking
  • Fishing
  • Biking on established trails
  • Bird Watching
  • Nature Photography
  • Dogs must be leashed from April 15 through August 15​




This area is a part of Maryland’s Department of Natural Resources public land system and is managed by the Wildlife and Heritage Service. The primary mission of the WMA system is to conserve and enhance wildlife populations and their respective habitats as well as to provide public recreational use of the State’s wildlife resources.

Eighty-five percent of the funding for Maryland's state wildlife programs comes from hunting license fees and a federal excise tax on sport hunting devices and ammunition. The federal aid funds are derived from the Federal Aid in Wildlife Restoration (or Pittman-Robertson) Fund, which sportsmen and women have been contributing to since 1937. Each state receives a share of the funds, which is administered by the U. S. Fish and Wildlife Service; these funds are used for wildlife conservation and hunter education programs, including the management of the WMA system.

Other sources of funds for land acquisition include Program Open Space Funding for Maryland's State and local parks and conservation areas, provided through The Department of Natural Resources' Program Open Space. Established in 1969, Program Open Space symbolizes Maryland's long-term commitment to conserving natural resources while providing exceptional outdoor recreation opportunities.​