The closure goes into place at 11.59pm on Tuesday and runs until the same time on 17 September, according to the US Department of Agriculture Forest Service’s Pacific Southwest Region.
The announcement comes weeks after the Forest Service closed nine national forests in Northern California.
“We do not take this decision lightly, but this is the best choice for public safety,” said Regional Forester Jennifer Eberlien.
“It is especially hard with the approaching Labor Day weekend, when so many people enjoy our national forests.”
Officials say the order doesn’t affect the Humboldt-Toiyabe National Forest because it’s not in the Pacific Southwest Region.
They hope that the order will reduce the number of people visiting the forests and becoming trapped by wildfires.
And they say less people in national forests decreases the chance of new fires starting, as well as limiting the spread of Covid-19, but anyone with a specific permit or anyone who is a federal, state or local officer carrying out an official duty is exempt from the ban.
Thousands of firefighters are currently battling the giant Caldor Fire as it rages near Lake Tahoe, which has burned 191,607 acres of forest and land since it started on 14 August.
And so far this year more than 6,800 wildfires have burned more than 1.7m acres across the state.
The Caldor Fire is one of around 90 major fires being tackled in the West and California alone is dealing with more than a dozen, which are being tackled by 15,200 firefighters.
As of Tuesday morning, Cal Fire said that 486 homes and 11 commercial properties had been confirmed destroyed, and firefighters are trying to protect thousands more in South Lake Tahoe, where an evacuation order was put in place in Monday.
More than 59,000 people, around 53,000 in El Dorado County alone , have been evacuated from their homes because of wildfires in the state, says the California Governor’s Office of Emergency Services.
Experts say that California’s landscape is extremely dry in 2021 after a dry winter and heatwaves hitting the state early in the year.
The climate crisis has also made the West warmer and drier, which increases the chances for more frequent wildfires and more dry fuel to burn.