Pulitzer Prize-winning writer and environmentalist Wallace Stegner once described the nation's national parks as "the best idea we ever had." He may have been right, but data indicate that travelling to visit the crown jewels of the system in the midst of a pandemic might not be a terrific idea, after all.

Using its COVID-19 online mapping tool, Social Explorer found that only one of the 28 counties that includes one of the 10 most-visited national parks has a higher rate of coronavirus than the U.S. average of 867 per 100,000 people. The parks, which reported 49.3 million visits last year, represent a wide geographic swath of the nation. The Great Smoky Mountains National Park, the busiest park with 12.5 million visits, is within a day's drive of almost half the U.S. population. Others, such as Glacier National Park in Montana, are a bit more remote and attract about 3 million visitors annually.

Cumulative Confirmed COVID-19 Cases on July 4th. Click here to explore further.

Regardless of the travel involved, a summer vacation to one of the crown jewels of the national parks system might seem even more attractive than usual to millions of Americans who have spent a month (or more) limiting their travel. Yet vacationers should be aware that as always, the parks are a mirror of the country: Thirteen of the 28 counties have seen rates of infection grow faster than the national average. By the Fourth of July, the infection rate in Park County, Wyo., home of Yellowstone National Park, had grown to 209.5 people per 100,000, a 2,936.2 percent increase since the May 25 Memorial Day holiday. On the other end of the spectrum, the rate of infection in Knox County, Maine, one of two counties that include Acadia National Park, was only 62.8 per 100,000 on July 4, a 25.1 percent increase from Memorial Day.

Risk is an individual calculation, never more so than now. Social Explorer can't assess risk for you, but we suggest following accepted social distancing and safety guidelines, and can provide data to help you make well-informed decisions about when and whether to visit some of the nation's most spectacular national parks this summer. The figures below show the number of visitors last year; the rate of confirmed infections as of July 4; and their growth between May 25 (Memorial Day) and Independence Day:

Great Smoky Mountains National Park

2019 visits: 12,537,743

Blount County, Tenn., 169.7 cases per 100,000, +166.0%

Sevier County, Tenn., 820.5 cases per 100,000, +996.9%

Cocke County, Tenn., 257.5 cases per 100,000, +354.9%

Swain County, N.C., 406.9 cases per 100,000, +479.6%

Haywood County, N.C., 162.2 cases per 100,000, +145.0%

Grand Canyon National Park

2019 visits: 5,974,411

Coconino County, Ariz., 1,502.7 cases per 100,000, +105.0%

Mohave County, Ariz., 659 cases per 100,000, +325.7%

Rocky Mountain National Park

2019 visits: 4,670,053

Larimer County, Colo., 233.9 cases per 100,000, +46.5%

Grand County, Colo., 139.4 cases per 100,000, +199.8%

Boulder County, Colo., 446.1 cases per 100,000, +53.7%

Zion National Park

2019 visits: 4,488,268

Washington County, Utah, 812.3 cases per 100,000, +375.9%

Iron County, Utah, 652 cases per 100,000, +635.9%

Kane County, Utah, 95.2 cases per 100,000, +133.3%

Yosemite National Park

2019 visits: 4,422,861

Tuolumne County, Calif., 79.7 cases per 100,000, +1,323.2%

Mariposa County, Calif., 159.6 cases per 100,000, +86.7%

Madera County, Calif., 372.9 cases per 100,000, +580.5%

Mono County, Calif., 317.5 cases per 100,000, +32.3%

Yellowstone National Park

2019 visits: 4,020,288

Park County, Wyo., 209.5 cases per 100,000, +2,936.2%

Teton County, Wyo., 594.1 cases per 100,000, +37.0%

Gallatin County, Mont., 274 cases per 100,000, +92.6%

Fremont County, Idaho, 61.7 cases per 100,000, 167.1%

Acadia National Park

2019 visits: 3,437,286

Hancock County, Maine, 31.2 cases per 100,000, +54.5%

Knox County, Maine, 62.8 cases per 100,000, +25.1%

Grand Teton National Park

2019 visits: 3,405,614

Teton County, Wyo., 594.1 cases per 100,000, +37.0%

Olympic National Park

2019 visits: 3,245,806

Clallam County, Wash., 56.4 cases per 100,000, +67.9%

Mason County, Wash., 84.6 cases per 100,000, +55.8%

Jefferson County, Wash., 123.2 cases per 100,000, +26.7%

Glacier National Park

2019 visits: 3,049,839

Flathead County, Mont., 64.2 cases per 100,000, +70.3%

Glacier County, Mont., 160.6 cases per 100,000, +266.7%

Author: Frank Bass