The state of Washington is well-known for its array of natural wonders, from state and national parks to wildlife refuges and waterways. However, the state also boasts a handful of hidden gems in the form of national monuments in Washington state that are well worth a visit for both out-of-state visitors and local residents.
The Three National Monuments in Washington State
Different from national parks, national monuments may be managed by one of eight federal agencies, including the National Park Service, U.S. Fish and Wildlife Service, U.S. Forest Service, Bureau of Land Management and even the Department of Energy. The President has the power to designate national monuments through the Antiquities Act of 1906, with 128 sites in 31 states and the District of Columbia currently named to the list.
Washington State is home to three of these special places: Hanford Reach National Monument, Mount St. Helens National Volcanic Monument and San Juan Islands National Monument. Below, we’ll take a closer look at each of the national monuments in Washington state and what makes them worth celebrating and protecting.

Hanford Reach National Monument
Established in the final year of the Clinton presidency, Hanford Reach National Monument is a 195,000-acre site surrounding the Hanford Nuclear Reservation, where the first plutonium reactors were developed and ultimately used to build the world’s first nuclear bombs.
This vast natural area hugs the Columbia River in the southern part of the state about an hour east of Yakima. Wildlife is abundant here, with coyotes, mule deer, bald eagles, elk and even porcupines a common sight in the desert landscape. Despite the often harsh conditions, wildflowers bloom in bright colors every spring, and the sagebrush canopy provides both a food source and shelter from the elements for many of the species who make their home in the monument.
Visitors will find plenty of opportunities for recreation at Hanford Reach, including hunting, birdwatching, hiking, boating and fishing; the waters of the Columbia River—as well as dozens of lakes, ponds and streams—teem with fall chinook salmon, mountain whitefish, sunfish and perch as well as carp and bass. This is one of the most beautiful national monuments in Washington state.

History buffs will appreciate the Cold War relics preserved at the monument, including the plutonium reactors along the river banks—one of which provided the fuel for the bomb dropped on Nagasaki, Japan on August 9, 1945, effectively ending World War II. A state-of-the-art interpretive center called The Reach also opened to the public in the last year, featuring exhibits exploring the area’s ecological significance as well as its role in the Manhattan Project.
Hanford Reach National Monument is managed primarily by the U.S. Fish and Wildlife Service. While basic facilities like restrooms are available, much of the monument is quite remote, and visitors should plan on being self-sufficient with drinking water and any other needed supplies.

Mount St. Helens National Volcanic Monument
Located about 100 miles south of Seattle, Mount St. Helens National Volcanic Monument was established by President Ronald Reagan in 1982, just two years after the volcano’s massive and deadly eruption blasted it into the national consciousness. Comprising 110,000 acres across three counties, Mount St. Helens National Volcanic Monument was set aside for research, recreation and education.

The monument offers a wide variety of activities for its half-million annual visitors, including cycling, hiking, camping, fishing, snow sports and ranger-led programs. Popular destinations within the monument include:
- The Johnston Ridge Observatory, which sends seismic, deformation and other data to the National Geological Service
- Ape Cave Lava Tube, a 2.5-mile tube-shaped cave that visitors can hike through year-round
- The Science and Learning Center at Coldwater, featuring exhibits, hands-on activities and interactive displays
…and hundreds of miles of hiking and equestrian trails. The monument’s landscape features rocky cliffs, lush green valleys, waterfalls and colorful wildflowers as well as a vast array of wildlife, such as deer, elk, bears, mountain goats and marmots.

San Juan Islands National Monument
Located in Puget Sound off Washington’s northwest coast, San Juan Islands National Monument is the most recently dedicated national monuments in Washington state, designated by President Barack Obama in 2013. This picturesque area encompasses 75 sites spread across roughly 1,000 acres within the San Juan Islands archipelago.
The monument is managed by the Bureau of Land Management and features a variety of stunning landscapes, from snow-capped peaks and thick green forests to sandy beaches and stately lighthouses. Hiking, boating, horseback riding and whale-watching are all popular activities here, and you’ll need access to some sort of watercraft to be able to see all 75 of the designated sites within the monument.

The islands are home to one of the most diverse ecosystems on the planet, and visitors may be fortunate enough to spot orcas, humpback and gray whales, harbor seals, sea lions, porpoises, starfish and hundreds of bird species—just to name a few. The plant life is just as diverse, with fir and cedar forests, large oaks, Pacific yews, big-leaf maples, native grasses and wildflowers and other flora thriving here.