Among them are 55 National Parks and 72 National Monuments. In 1998 the NPS units were visited by 287 million people. The amount charged differs per park. The entrance permit is often valid for 3 or 7 days. If you enter the park on foot or by bike a fee per person is charged.
Most parks also offer anual passes.
National Parks pass If you are planning to visit several parks you might consider purchasing an National Parks Pass. The pass can be purchased at any NPS unit and covers the entrance fees for most of the NPS units like national parks en monuments. However the pass is not valid for some national parks. The National parks passpor is what used to be the Golden Eagle Pass.