Places We Protect

Cox Island Preserve


Aerial view of tidal creeks and marshlands of Cox Island.
Cox Island, Oregon Cox Island, Siuslaw Forest © Roy Lowe

An island saltmarsh on Oregon's central coast supports eel grass, egret and muskrat.



Effective April 1, 2021, this preserve is open to the public. Please observe social distancing guidelines, follow all posted site usage/visitation guidance and wear a mask whenever encountering other guests. Use of unmanned aerial vehicles (UAVs or “drones”) is prohibited on or over the preserve. This property is privately owned and managed in order to protect the sensitive species that call it home. We appreciate your help in protecting the landscape and respecting all those who enjoy it.

What Makes Cox Island Special

Seven miles inland from the Pacific Ocean, this island on Oregon's central coast is an excellent example of an estuarine saltmarsh ecosystem. Low elevation leads to daily floods at high tide. At low tide, the island is dissected by a maze of tidal channels, adjoined by expanses of mudflats.

What TNC Has Done/Is Doing

Volunteers help control the only known Oregon population of saltmeadow cordgrass (Spartina patens), an invasive, introduced species that threatens native wetland vegetation. Researchers believe it arrived decades ago in packing material for clams, and TNC ecologists and volunteers are working to control the species and prevent it from spreading to other coastal marshlands.


Limited Access

Cox Island is only accessible by boat


187 acres

Explore our work in Oregon

Please observe the following guidelines while visiting:

  • Stay out of the old house on the property as it is no longer structurally sound.
  • No dogs. Preserves harbor ground-nesting birds and other wildlife that are extremely sensitive to disturbance.
  • Please observe social distancing guidelines, follow all posted site usage/visitation guidance and wear a mask whenever encountering other guests.
  • No bicycles or motorized vehicles. Native plants and research sites are easily trampled.
  • No hunting, camping or campfires.
  • For groups of 10 or more, please contact us before visiting a preserve (a volunteer naturalist guide may be available).
  • Please bring a bag and carry out any trash you find.
  • Please report to us any problems you observe (e.g., camping, plant removal, hunting, off-road vehicle damage, etc).



What to See: Plants

The preserve supports several important habitats including eel grass (Zostera marina) beds in the lower estuary and Henderson’s checkermallow (Sidalcea hendersonii).


What to See: Animals

Abundant with softshell clams and shrimp, the nutrient-teeming mudflats provide feeding grounds for great blue herons from nearby rookeries. More than 80 species of birds and waterfowl, including great egrets, phalaropes, whimbrels and short-billed dowitchers are known to visit this largely undisturbed coastal marsh. Island residents include beaver, river otter, muskrat and mink. In addition, hawks and ospreys are commonly seen.

Due to extreme tidal fluctuations, special care is needed to ensure that boats are safely tied up and secured. Please visit the preserve during low tide only in the spring and summer. There are no official trails. Foot travel is difficult because small, but deep, tidal channels are often covered by vegetation.

Stand Up for Nature in Oregon

The mission of The Nature Conservancy is to conserve the lands and waters upon which all life depends, and for nearly 60 years, we've been working in Oregon to do just that. We're bringing people together to solve the biggest conservation challenges of our time by transforming policy, inspiring communities to take action, protecting vital habitats and natural resources and improving livelihoods.

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.

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