CONCORD, N.H. — Some privately-run campgrounds in New Hampshire’s White Mountains National Forest will be forced to close ahead of the lucrative Columbus Day weekend because of the federal government shutdown, according to the U.S. Forest Service.

The closure of the 21 campgrounds and hundreds of camping sites comes at a particularly bad time: Early October is peak season for leaf-peeping and the long weekend is the third best for tourism in the state, behind the Fourth of July and Labor Day, according to New Hampshire tourism officials. Last year, some 600,000 people visited over the weekend, pumping nearly $90 million into the economy.

About 165 state and private campgrounds that do not contract with the federal government will remain open.

A spokesman for the U.S. Forest Service said not all campground operators have been notified yet because federal offices are down to skeleton crews during the shutdown. National parks and monuments are also closed.

Spokesman Leo Kay said private businesses that contract with the federal government must close because rangers and other federal employees provide support, services and oversight. “The private concessionaires are unfortunately impacted by the shutdown, as are many private businesses,” he said in an email.

He said the closures in the 800,000-acre White Mountain forest mirror those happening across the country at sites that contract with the National Park Service and other federal land management agencies. The same policy was in place during the government shutdown in 1995 and 1996.