Looking for something fun to do outdoors this holiday weekend? Head to a national park-for free!

The president has once again deemed all national parks free and open to the public this weekend in honor of National Parks Week.

Yellowstone National Park Getty Images

In addition to free entrance, during National Parks week, which lasts April 19-27, visitors can partake in special events and programs, as well as National Junior Ranger Day on April 26.

According to National Park Services, 133 of the nation's 401 national parks usually charge an entrance fee, including Grand Canyon, Denali, Yellowstone, Shenandoah, and the Statue of Liberty.

The U.S. National Park systems covers more than 84 million acres and includes every state.

In 2013, U.S. state parks saw more than 273-million visitors, with Golden Gate seeing the most visitors last year.

Other days you can grab free park entrance include: Martin Luther King Jr. Day, Presidents Day weekend, National Park Service Birthday on August 25, September 27 for National Public Lands Day, and November 11 for Veterans Day.

So get out there and enjoy the great outdoors. Or in the words of Obama: "I encourage all Americans to visit their National Parks and be reminded of these unique blessings we share as a Nation."