The National Parks Have Never Been More Popular But you can still avoid a crowd if you head for the Arctic Circle.

As the National Park Service prepares to celebrate its centennial in August, the national parks have never been more popular.

Total recreational visits to all NPS sites topped 300 million in 2015, an astounding 14 million increase from 2014. (In addition to the national parks, NPS sites include national historic sites, national monuments, national lakeshores and seashores, and so on.) Homing in on just the 58 national parks that reported visitation in 2015, recreational visits totaled 75.3 million, besting the 1997 record of 69.5 million.

I’ve contributed to this trend, having visited 12 national parks in 15 visits since 2004. Some of my family members have lived outside Yellowstone for more than 20 years, and they report seeing the park grow increasingly busy during peak season (June through August). That’s backed up by the numbers: Visitation to national parks is up 12 percent since 1996 and grew 18.6 percent in just the past two years (to 75.3 million from 63.5 million).

(Although total visitation is at an all-time high, visitation has declined on a per capita basis — as some researchers have pointed out — to 21.6 visits per 100 people in the U.S. in 2014 from a peak of 25.8 visits per 100 people in 1995.)

What explains this burst in popularity of the national parks?

“You mean besides the price of gas?” said Jeff Olson, a National Park Service spokesman. With gas prices below $3 per gallon last year, visitation surged. “When the price of gas goes up, visitation stutters. Then visitors get used to the price of gas, and visitation returns,” he said.

Pam Ziesler, the program coordinator for the NPS’s visitor use statistics, voiced another theory: “Visitors are saying it has to do with good weather. We had a beautiful spring and fall last year.” Weather can greatly affect visitation, particularly in the shoulder seasons (early spring and late fall). “But we have no firm, data-driven evidence” explaining the growing popularity of the parks, she said.

The NPS, in concert with the National Park Foundation, a charitable foundation, recently launched a promotional campaign including a platform to display Twitter and Instagram posts of people enjoying the parks ahead of the centennial, and that could be driving up visitation too. “We targeted the millennials. Those are the people we want to connect with and cultivate as the next generation of park visitors, supporters and activists,” Olson said.

The most popular park, by far, in terms of recreational visitors is Great Smoky Mountains National Park, in Tennessee and North Carolina. It has averaged nearly 10 million visitors per year since 1996, more than double that of Grand Canyon National Park, the second most visited. What makes Great Smoky Mountains so popular? Olson points out that it’s one of the few national parks that charge no fee, and it’s near Interstate Highway 40. That makes it an accessible drive from big cities including Atlanta; Charlotte, North Carolina; Nashville, Tennessee; and Louisville, Kentucky.

After Grand Canyon National Park, next in popularity are Yosemite, Olympic and Yellowstone national parks. The least-visited parks are in American Samoa and Alaska. Kobuk Valley National Park, above the Arctic Circle in northern Alaska, did not report visitation in 2015 (and is not included in the table here).

PARK LOCATION AVERAGE ANNUAL VISITORS Great Smoky Mountains NC, TN 9,572,089 – Grand Canyon AZ 4,449,030 – Yosemite CA 3,615,372 – Olympic WA 3,216,918 – Yellowstone WY, MT, ID 3,155,627 – Rocky Mountain CO 3,061,745 – Cuyahoga Valley OH 2,803,247 – Zion UT 2,674,496 – Grand Teton WY 2,620,022 – Acadia ME 2,421,256 – Glacier MT 1,944,050 – Hawaii Volcanoes HI 1,440,608 – Hot Springs AR 1,379,952 – Joshua Tree CA 1,356,098 – Haleakala HI 1,346,916 – Shenandoah VA 1,278,292 – Mount Rainier WA 1,215,781 – Mammoth Cave KY 1,199,348 – Bryce Canyon UT 1,163,925 – Everglades FL 1,026,046 – Death Valley CA, NV 980,140 – Sequoia CA 959,333 – Badlands SD 932,074 – Arches UT 925,767 – Saguaro AZ 685,738 – Petrified Forest AZ 660,023 – Wind Cave SD 655,503 – Capitol Reef UT 631,291 – Virgin Islands VI 570,028 – Kings Canyon CA 549,517 – Mesa Verde CO 528,569 – Theodore Roosevelt ND 501,255 – Biscayne FL 485,730 – Crater Lake OR 460,761 – Carlsbad Caverns NM 444,142 – Canyonlands UT 436,859 – Channel Islands CA 420,067 – Glacier Bay AK 417,135 – Denali AK 405,998 – Redwood CA 402,224 – Lassen Volcanic CA 385,168 – Big Bend TX 333,408 – Great Sand Dunes CO 274,835 – Kenai Fjords AK 272,669 – Voyageurs MN 230,550 – Pinnacles CA 187,639 – Guadalupe Mountains TX 187,455 – Black Canyon of the Gunnison CO 184,520 – Congaree SC 105,020 – Great Basin NV 87,343 – Dry Tortugas FL 64,414 – Wrangell-St. Elias AK 53,110 – Katmai AK 48,403 – North Cascades WA 23,059 Isle Royale MI 18,216 Gates of the Arctic AK 9,358 Lake Clark AK 8,524 National Park of American Samoa AS 7,067 The most popular national parks over the past 20 years Average annual recreational visitors, 1996-2015 Source: national park service

The Great Smoky Mountains National Park has kept its title as the most-visited park since 1944. Grand Canyon National Park, however, has been No. 2 since only 1990. Acadia (in Maine) was the second-most-visited national park from 1979 to 1989 but has fallen to No. 9.

The NPS has data on recreational visits going back to 1904, more than a decade before the agency was created, but began tracking more detailed data on visits, including overnight stays, in 1979. Total overnight stays are down 6 percent since 1979, to 6.3 million from 6.7 million. But overnight stays are up 21 percent since bottoming out at 5.2 million in 2008.

Backcountry and tent overnight stays have increased in recent years, up 34 percent and 16 percent, respectively, since 1979. (Since I have backcountry camped at Yellowstone and Grand Teton in the past three years, this rings true. Even the remote campsites are sometimes hard to reserve.) Miscellaneous overnight stays, referred to in the chart here as “groups and miscellaneous,” are primarily camping in organized groups, such as a work retreat or Girl Scout trip. They make up 9 percent of all overnight stays and have also grown (23 percent since 1979).

RV camping, however, is dead — or dying, at least. It has declined 46 percent since 1979 and now makes up less than one-quarter of all overnight stays across the national parks.

But this is just recreational visitors, who make up about three-quarters of all visitors to the national parks. The other quarter are nonrecreational visits, and they have more than doubled in number since 1979. Nonrecreational visitors include commuters, conference attendees, research scientists and employees who work at businesses within the park.

Visits — defined as “a person in a park on a day” — are just one way to measure park usage. Total hours spent tell a different story. “Visitor hours are equally important when looking at impacts on facilities, roads, staffing, etc.,” Ziesler said. Total hours include overnight stays and better reflect intensity of use. By this metric, Grand Canyon and Yellowstone national parks had the highest recreational hours in 2015. Overall, total recreational hours are up 37 percent since 1979, while nonrecreational hours are about flat.

Although the rock-star parks such as Yellowstone, Grand Tetons, Zion and others are incredible, they’re also equally busy. In my experience, some of the best times can be had at the less-visited parks. Cumberland Island National Seashore in Georgia, for example, was one of the wildest and most beautiful places I’ve ever visited.