National Public Lands Day was established in 1994, and on the 4th Saturday every September, this special day is celebrated across the nation. National Public Lands Day is the largest volunteer effort in the United States, and it aims to celebrate the connection between people and green spaces in their communities. To mark the important day, entrance to all national parks in the United States is free for visitors on National Public Lands Day.

There are more than 400 places available to visit, and fee-free days are a great way for visitors to check out a new place or enjoy an old favorite. The National Park Service has a total of 61 national parks and 419 units, which cover more than 85 million acres in all 50 states, D.C. and U.S. territories. A unit can include a site like a recreation area, trails, monuments, parks, battlefields and much more.

Normally, entrance fees range widely depending on the park, but many places charge up to $35 per vehicle or $20 per person, not including parking permits. However, of the 418 parks, historic and cultural sites, and monuments, only 112 of them charge entrance fees.

If you are too busy or can't make it, don't worry, there are five days a year that parks are free to all. The next free day is on November 11 to celebrate Veterans Day. If you don't want to fight the inevitable crowds on free days, you can purchase the $80 America the Beautiful National Parks and Federal Recreational Lands Pass. With the annual pass, you can visit all national parks, along with more than 2,000 recreation sites, all without having to pay entrance fees. Those in the U.S. Military can enjoy complimentary annual passes. You can learn more about the different passes available here.

Adam Luehrs is a contributing writer at GET.com based in California. He likes traveling to new and exciting destinations, preferably on his credit card company's dime. When not on the road, Adam enjoys hiking around the mountains of San Diego, trying out new food and reading history books. Email: adam.luehrs@get.com.