Heads up, budget travelers: The National Park Service this week announced six “entrance-fee free” promotions throughout 2017. This means that 120 park sites that normally charge visitors to get in will offer complimentary admission to everyone on those days. 

The fee waiver includes entrance fees, commercial tour fees, and transportation entrance fees. Other fees (such as those for campsites or third-party concessions) are not included.

Specifically, there are 10 free days in all. The first one is right around the corner, on Martin Luther King, Jr. Day next week. Other days with no entrance fee:  

- February 20: Presidents’ Day

- April 15-16, 22-23: Weekends on either side of National Park Week

- August 25: National Park Service birthday

- September 30: National Public Lands Day

- November 11-12 Veterans Day weekend 

Annual free days aren’t the only way to access national parks without forking over cash at the entrance gate. There are more than 400 NPS sites across the country, and about 280 of them are free all the time. In addition, any fourth-grade student can get a free annual pass through the Every Kid in a Park program, which seeks to provide opportunities for children and their families to appreciate nature. Active-duty military and citizens with permanent disabilities also always can get in gratis.

When you have to pay at the gates, national park fees run between $3 and $30, with some parks offering week-long entrance. 

Compared to certain theme-park tickets that run more than $100, the price of admission at national park sites is a downright steal. 

The year 2017 marks the beginning of the National Park Service’s second centennial of operation. The Park Service was created on August 25, 1916, by President Woodrow Wilson, and the organization spent last year celebrating its 100th anniversary with special events at parks across the country.

Want to learn more? Check out all our information about our great country’s National Parks.

Matt Villano is a freelance writer and editor based in Healdsburg, California. In nearly 20 years as a full-time freelancer, he has covered travel for publications including TIME, the Wall Street Journal, the New York Times, Sunset, Backpacker, Entrepreneur, and more. He contributes to the Expedia Viewfinder blog and writes a monthly food column for Islands magazine. Villano also serves on the board of the Family Travel Association and blogs about family travel at Wandering Pod. Learn more about him at Whalehead.com.