The National Park Service says Hawaii's seven national parks drew 5.1 million visitors in in 2012.
The report released Monday says visitors spent $314.5 million in the areas around the attractions, which include active volcanoes, lush trails and historic sites. That helped support more than 3,700 jobs.
Hawaii Volcanoes National Park on the Big Island was the most popular park in the state with 1.5 million visitors.
Executive Director Ross Birch of the Big Island Visitors Bureau says the economic impact isn't surprising given the park's popularity.
The estimated economic impact includes money spent by visitors at businesses near the parks and dollars spent by the employees and vendors of those companies.