Coinciding with the first day of summer is another entrance-fee-free-day in the National Park System.

“The longest day of the year (June 21) is the perfect time to take a short trip," National Park Service Director Jon Jarvis said in announcing the free day in the parks. "Celebrate an extended Father’s Day with Dad, the start of summer break with the kids, or a job well done with your favorite graduate.

"With 394 national parks across the country, you could opt to visit an old favorite or explore a new place. Find a reason to get outside and enjoy the extra sunshine at a national park near you.”

Among the suggested activities you might enjoy in the parks on June 21:

* Soak in the day’s first rays on top of Cadillac Mountain in Acadia National Park, a traditional spot in Maine to watch the sun rise;

* Mark the annual summer solstice with a solstice program at Casa Rinconada in Chaco Culture National Historical Park in New Mexico;

* Take a free bus tour of Zion National Park in Utah or Tallgrass Prairie National Preserve in Kansas or a scenic wagon ride at Oxen Cove Farm in Maryland;

* Get a free Cajun dance or music lesson at Jean Lafitte National Park and Preserve in Louisiana;

* Watch a sled dog demonstration at Denali National Park and Preserve in Alaska, or;

* Tour the Three Sisters Lighthouses in Cape Cod National Seashore in Massachusetts.

Additional fee free days in 2011 are National Public Lands Day (Saturday, September 24) and Veterans Day weekend (November 11-13).