Yellowstone National Park is celebrating a big jump in the number of visitors that are exploring the park.

"We are up 24% from last year," said Yellowstone National Park Public Information Officer Traci Weaver. "The recreational visits from January through May were 515,693 visits. It was definitely busy. For May alone, it was 383,670 visitors."

Although the crowds are welcome, Weaver says it is hard to pinpoint what is driving the increase in attendance.

"A mild winter and early spring played a key role, but there are a lot of other factors as well," Weaver said. "I think there are a lot of things going on including the 'Find your Park' campaign that launched in April, as well as lower gas prices, and the economy rebounding a little bit. We've just seen a lot of visitors."

The “Find your park” campaign was partly motivated by polling which showed that many people that live in communities adjacent to National Parks, hadn’t taken the time to actually visit them.