Credit: USGS site
The old Golden Age Passport is no longer issued, but has been replaced by the America The Beautiful Senior Pass. After age 62, you can apply for the pass for a $10 processing fee, and it is good for a lifetime, or until you lose it. If you misplace it, you have to buy a new one. It provides benefits that are accepted by the Corps of Engineers, Bureau of Land Management, Bureau of Reclamation, Fed. Fish and Wildlife, USDA Forest Service and National Park Service. Since each agency, and even facilities within an agency, have different fee schedules, the amount of discount varies, but the point being that discounts are provided. These may include such things as admission, camping fees, special use permits, tours, and the services of concessionaires at over 2,000 facilities nationwide.
Access Passes are also available free for those able of document a permanent disability.
Internet sites still say you can apply by mail, but another fringe affect of 9-11, is you have to both apply in person, and pick the pass up in person with acceptable proof of identity. We used our passports. For us, this meant we had to travel over 400 miles to accomplish the two trips, so our costs for the pass were over a hundred dollars. It will take awhile to make that up.
When you visit a state or county facility, also ask if they will honor the senior pass. Some will, and others, like Oklahoma parks, will not.