JACKSON — The hordes flowing through Yellowstone National Park will be required to wear masks in dozens of areas, indoors and out, this summer.

The National Park Service itself has not mandated masks to blunt the spread of COVID-19, but Xanterra, the park’s largest concessionaire, has decided face coverings are a must.

The Colorado-based business, which manages lodging, restaurants, gift shops and more in the park, made the announcement Wednesday.

“We believe it’s the responsible thing to do, given the current climate with the health situation around the country and within the region,” Mike Keller, Xanterra’s general manager for Yellowstone, told the Jackson Hole Daily.

The mask requirement covers all indoor Xanterra facilities in Yellowstone and other parks where it operates: Death Valley, Glacier, Grand Canyon, Mount Rushmore, Rocky Mountain and Zion.

Staying outside won’t shield all Xanterra customers from the mask mandate. Where recommended social distancing is not possible — such as while waiting for a horseback ride or a scenic boat ride — they will be required, Keller said.

“It includes if you’re queuing in line to go inside a building,” he said. “It’s not speaking for all land in Yellowstone, just in the outdoor areas that we operate within.”

Xanterra operates facilities throughout the 2.2 million-acre park’s road system, including in Grant Village, Old Faithful, Tower Falls, Lake Yellowstone, Mammoth Hot Springs and Canyon. The company accounts for many of the seasonal employees in Yellowstone, with a typical summer workforce of about 3,500, dwarfing the Park Service’s 500 federal employees.

This year, because of coronavirus-related housing restrictions, the respective staff sizes are vastly reduced, approximately 800 and 200, respectively.

Xanterra’s decision to mandate mask wearing comes as businesses and governments large and small are making the call to do the same thing, prompted partly by the highest rates of domestic COVID-19 spread since the pandemic began and the United States failing as a nation to curb the spread.

Teton County health officials have submitted a draft mask order that is being reviewed by the state (see the story on page 1), and California has mandated masks statewide in almost all indoor public spaces and even in outdoor lines to access public buildings.

So far, concessionaires that operate in Grand Teton National Park have not followed Xanterra’s lead. Two of Grand Teton Lodge Company’s largest indoor public spaces — Jackson and Jenny Lake lodges — aren’t opening this year, though some visitor services at Colter Bay and Flagg Ranch are open.

Lodge company President Alex Klein said in an emailed statement that mask use is encouraged in its indoor Teton park spaces, and that he’s supportive of the county’s draft order currently under state review.

Teton park spokeswoman Denise Germann said that there has been no discussion — at least that she’s aware of — about other concessionaires or the park itself elevating its mask recommendation guidance to a requirement.

Its recommendation carries over to visitor centers, which have opened up with some changes in Grand Teton.

“I think everybody, including the park, is highly encouraging face coverings,” Germann said.

It’s the same story for facilities directly operated by Yellowstone, although its visitor centers remain closed.

Yellowstone “strongly” encourages people in visitor centers to wear appropriate protection, park spokeswoman Morgan Warthin said in an email.

Before Xanterra’s mask requirement took effect, only 20% to 40% of its customers were wearing masks in its Yellowstone indoor spaces, Keller estimated. Folks now will encounter a door attendant at every building whose duties include counting the inflow and outflow of people and distributing free masks to those who need them.

It’s too early to say how many masks Xanterra will be doling out daily in Yellowstone, Keller said, but it’s bound to be in the thousands.