A baker's dozen, and then some. That's how many entrance-fee-free days are on the 2016 calendar for the National Park System. In all, there are 16 days next year when entrance fees won't be charged park visitors.

The 16 entrance fee-free days for 2016, the National Park Service's centennial year, are:

* January 18 – Martin Luther King, Jr. Day

* April 16 through 24 – National Park Week

* August 25 through 28 – National Park Service Birthday (and following weekend)

* September 24 – National Public Lands Day

* November 11 – Veterans Day

“Fee-free days provide an extra incentive to visit a national park, especially during next year’s centennial celebration,” said National Park Service Director Jon B. Jarvis. “We added extra fee-free days so that everyone has a chance to join the party. With locations in every state, finding a national park is easy. The hard part might be deciding which ones to visit.”

To honor the National Park Service’s centennial, the National Park Foundation has joined the National Park Service to launch a public engagement campaign called Find Your Park to help all Americans discover all the things that national parks can be. Visit FindYourPark.com for a list of centennial special events across the country and to learn how to discover, explore, recreate, be inspired, or simply have fun in national parks.

Usually, 127 of the 409 National Park Service sites charge entrance fees that range from $3 to $30. The entrance fee waiver for the fee-free days does not cover amenity or user fees for things like camping, boat launches, transportation, or special tours.

To continue the national park adventure beyond these fee free days, the $80 America the Beautiful National Parks and Federal Recreation Lands Pass allows unlimited entrance to more than 2,000 sites, including all national parks, throughout the year. There are also a variety of free or discounted passes available for senior citizens, current military members, fourth grade students, and disabled citizens.

On August 25, 1916, President Woodrow Wilson signed the act that created the National Park Service “to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for future generations.”

Today, the National Park System includes more than 84 million acres and is comprised of 409 sites with 28 different designations, including national park, national historical park, national monument, national recreation area, national battlefield, and national seashore. Collectively, these sites contain more than 18,000 miles of trails, 27,000 historic and prehistoric structures, 247 species of threatened and endangered species, and 167 million museum items.

Last year, almost 293 million people visited national parks. Those visitors spent $15.7 billion in local communities which supported 277,000 jobs and had a $29.7 billion effect on the economy.

But the impact doesn't stop there. In addition to national parks, the National Park Service works with tribes, local governments, nonprofit organizations, and businesses across the country to help preserve local history and create close-to-home recreational opportunities. Programs such as the National Register of Historic Places, National Heritage Areas, National Wild and Scenic Rivers, National Historic Landmarks, National Trails, and the Rivers, Trails, Conservation Assistance Program revitalize communities, preserve local history, celebrate local heritage, and provide places for children and families to get outside, be active, and have fun.