Yellowstone National Park, known for its hot springs, geysers, wildlife and breathtaking scenery, is on track to set a new record for visitors in 2010.
More than 2.5 million people flocked to Yellowstone from June through August, a pace that would break the record of nearly 3.3 million visitors tallied in 2009, said park spokesman Al Nash.
Yellowstone, the best known of U.S. national parks stretching across the states of Montana, Wyoming and Idaho, saw visitor numbers in August surge well beyond the 800,000 mark for the first time in its 138-year history.
Nash said the August figure is up 81,000 from the previous record for that month, which was set in 1995, when 773,307 people visited the park.
In a typical year, more visitors pack the country's oldest national park in July than in any other month, followed by August, June, September and May.
Yellowstone is not alone among parks in the Rocky Mountain West to report an upswing in visitors.
Glacier National Park in northwestern Montana saw near record visitation in August for the second month in a row, said spokeswoman Amy Vanderbilt.
That park, named for its glacier-carved terrain and remnant glaciers, is among several registering higher-than-average numbers this year for activities like group camping.
Park officials say the economy has played a role in Americans' return to less costly vacation activities like hiking and camping. But they also point to Ken Burns' six-episode series on national parks that aired on PBS last fall.
"National parks overall are seeing an increase in recreation," Vanderbilt said.