If you need another excuse to get outside and enjoy the beautiful spring weather, the National Park Service is offering free admission to all National Parks – all 397 of them! – from April 21 through April 29, 2012 during National Park Week.

While most parks are free and open to the public year round, over 100 parks charge a fee to enter. The National Parks that usually charge admission include the Grand Canyon, Joshua Tree, Yosemite, the Everglades, Yellowstone, Bryce Canyon, Arches National Park, and many more. But during National Park Week, all entrance fees, commercial tour fees, and transportation entrance fees are waived.

There will also be events throughout the week at various parks across the country, like Volunteer Day on April 21, where you can get your hands dirty with local projects, Earth Day on April 22, and National Junior Park Ranger Day on April 28, where kids can be sworn in as Junior Rangers.

If you need trip ideas or inspiration, check out our Top Ten National Park Hikes. And if you’re interested in making your visit into a longer excursion, check out the National Parks Promotion Council – they rounded up a bunch of deals for lodging, restaurants, and tours near the parks.

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