On Saturday, Zinke tweeted, "Not all national parks are fully open but we're working hard to make as much accessible as is safely possible".
National Parks and other federal public land will primarily remain open even if the government shuts down tonight, according to Department of Interior spokeswoman Heather Swift.
During the last government shutdown, monuments were blocked off with barricades and parks were closed, an obvious inconvenience to tourists.
But a spokesperson for the Department of the Interior told reporters, "services that require staffing and maintenance such as campgrounds, full service restrooms, and concessions will not be operating". McClintock indicates that contingency plans for businesses in the park are now being worked out by National Park Service officials.
A government shutdown could disproportionately harm those communities if parks remained closed.
"Because of the government shutdown, that had to be closed today, so the information could not be provided by the rangers", he added.
The Trump administration has National Park Service officials across the country to maintain public access at parks "unless access presents a serious and imminent threat to human life, safety, or health, or a serious and imminent threat to the condition of a sensitive natural or cultural resource".
Outside the park, both Yellowstone's NPS website and social media have been suspended.
Federal sites, parks, and landmakrs throughout Wyoming will be closed until the budget issue is resolved.
At the Springfield Armory National Historic Site, the lawn will remain open. Eleanor Holmes Norton that allows D.C.to use local funding to stay open during federal shutdowns.
The National Park Service said it would close some areas either to preserve the park (such as a trail open to visitors only by ranger-guided tour) or for safety (such as a skiing trail that rangers normally monitor for avalanche risk). In the event of unsafe conditions, all park roads and developed areas will close.
"It's very, very disorganized, maybe because we've been at the brink of the cliff so many times", Cox said. But the National Park System also includes buildings like Ford's Theater in Washington, where President Abraham Lincoln was shot, and Independence Hall in Philadelphia, where the Declaration of Independence and Constitution were signed.
Access is not restricted on U.S. Forest Service land, but services will be unavailable.
In New Mexico, parts of Bandelier National Monument's cliff dwellings and fragile archaeological sites were off-limits to protect them from damage, but the entrance road and some trails were open.
Skiing and snowboarding is still available at Jackson Hole Mountain Resort, Grand Targhee, Snow King, and White Pine Ski areas.