National Park Week happens in April each year.
All National Parks waive their entrance fees during that week. If you are anywhere
near a National Park, National Monument, National Seashore, National
Battlefield, National Historical Site that normally charges entrance
fees, National Park Week is a good time to get in free.

If you
miss out on the National Park Week offer, we recommend that you obtain
or buy one of the following passes, especially if you plan to sightsee
at numerous national parks within the year:

• America the Beautiful – 2013 Annual Pass – $80 (AKA Interagency Annual Pass):
  Good
  at all national parks, seashores, monuments, etc., and federal
  recreation areas. The pass admits the pass holder(s) and passengers in a
  non-commercial
  vehicle at “per vehicle” fee areas, and pass holder plus three adults at
  “per person” fee areas. (Children under 16 are admitted free.)
  The pass is good for one year from the date of purchase. The pass is not
  valid for Expanded Amenity Fees such as camping or parking at Mt.
  Rushmore. This pass can be purchased by mail or at a national park visitor center or entry gate.
• Free Annual Pass for Military (AKA Military Annual Pass):
  For active duty military personnel and dependents with proper identification. Pass must be issued in person.
• America the Beautiful – Senior Pass – $10 (AKA Interagency Senior Pass):
  This is a lifetime
  pass for U.S. citizens or permanent residents age 62 or older. The
  Senior Pass can only be obtained in person at a park. The pass admits
  the pass holder(s) and passengers in a non-commercial
  vehicle at “per vehicle” fee areas, and pass holder plus three adults at
  “per person” fee areas. (Children under 16 are admitted free.) The
  Senior Pass provides a 50% discount on some Expanded Amenity Fees
  charged for camping, swimming, boat launch and specialized interpretive
  services. In some cases where Expanded Amenity Fees are charged, only
  the pass holder will be given the 50% reduction.
• America the Beautiful – Access Pass – Free. (AKA Interagency Access Pass):
  This is a lifetime
  pass for U.S. citizens and permanent residents with permanent
  disabilities. The Access Pass can only be obtained in person at a park
  entrance or visitor center. Documentation is required to obtain the
  pass. Acceptable documentation includes: statement by a licensed
  physician; document issued by a Federal agency such as the Veteran’s
  Administration, Social Security Disability Income or document issued by a
  State agency such as a vocational rehabilitation agency. The pass
  admits the pass holder(s) and passengers in a non-commercial
  vehicle at “per vehicle” fee areas, and pass holder plus three adults at
  “per person” fee areas. (Children under 16 are admitted free.) The
  Accesss Pass provides a 50% discount on
  some Expanded Amenity Fees charged for camping, swimming, boat launch
  and specialized interpretive services. In some cases where Expanded
  Amenity Fees are charged, only the pass holder will be given the 50%
  reduction.
• America the Beautiful — 2013 Volunteer Pass – Free :
  This
  pass is for volunteers who acquire 250 service hours on a cumulative
  basis. Good for one year beginning with the date of the award. The pass
  admits the pass holder(s) and passengers in a non-commercial vehicle at
  “per vehicle” fee areas, and pass holder plus three adults at “per
  person” fee areas. (Children under 16 are admitted free.)
• Some of the major National Parks also have a park-specific annual pass for $50.

Bob
and I love frequenting national parks. Even when we think there may not
be anything interesting there, we’re wrong. We love exploring trails,
reading history, checking the visitor centers for geology and animals in
the park, and absorbing the experience. Each park is different.

Summer’s
coming. I urge you to get out and explore our national parks and
federal recreation sites. Hike, discover, fish, watch sunsets, go on
ranger-led tours, photograph, smell the air, search for wildlife, and
have fun!