The state Department of Natural Resources is closing all DNR-managed lands to the public for two weeks starting Thursday, March 26.
DNR manages more than 80 sites, including popular trails like Mailbox Peak, Rattlesnake Ledge and Mount Si.
Campgrounds remain closed through April 30.
"This was not an easy decision. We treasure our forests and trails and beaches as places of rejuvenation and refuge from the chaos of daily life. But, I cannot ignore the unfortunate reality of what we saw this weekend: crowded trails, people shoulder to shoulder, and large gatherings," Commissioner of Public Lands Hilary Franz said. "This behavior undercuts the sacrifices that Washingtonians of all means and ability are making in order to adhere to social distancing. And it undercuts the heroic efforts of our doctors, nurses, and first responders who risk their lives each day responding to this unrelenting epidemic.
“This behavior also makes clear that, while we have taken drastic measures, we have not done enough when it comes to closing areas where large crowds gather and communicating the importance of staying at home and avoiding physical contact with others."
State recreation sites aren't the only nature destinations closing down. Olympic and North Cascades national parks closed campgrounds and facilities, as well as some trailheads and access roads. On Tuesday afternoon, Mount Rainier National Park closed all park roads to public vehicles including bicycles.