The word geocaching is a participle made from the roots geo meaning “Earth” and cache meaning “a temporary stash,” and it was coined by Matt Stum. People around the world go geocaching, using GPS and maps to locate caches that others have hidden for the sake of the game. The term geocache refers to the hidden treasure being sought. And a person who engages in geocaching — either hiding geocaches or seeking them — is called a geocacher.
Geocaching came about in 2000 when the government of the United States stopped a policy of degrading the GPS (Global Positioning System) signals that were publicly available. The policy, Selective Availability, had meant that GPS readings could be inaccurate by 300 ft (91.44 m), and it had been applied in order to allow the military to protect sensitive areas. With its deprecation, GPS accuracy came to be within 6 to 20 ft (1.83 to 6.1 m). Dave Ulmer, an early GPS enthusiast, hid a cache in a remote part of Oregon to test the new GPS functionality, and posted the coordinates on the Internet. He left a logbook, along with a pencil and a couple of inexpensive “treasures” in the box, and within three days, two people found the box, making these three people the first to earn the name geocacher.
Geocaches are typically hidden in waterproof containers in places in which it is legal and acceptable to hide something, and where the presence of a container and lots of geocachers searching for it will not adversely impact the environment or cause alarm. The items customarily placed inside the cache — logbook, writing utensil, and treasures — are typically each placed within one or more zip-top plastic bags, as suggested by local environmental conditions and the exact location of the cache. The container and the logbook are marked with the site’s latitude and longitude as determined by several readings, and then posted online on one of the geocaching sites. The geocacher locating the site makes an entry in the log, exchanges trinkets, and reports the find online, with being the first finder gaining accolades.
There are a number of standard variations that a geocacher may introduce into his or her cache, but the original geocacher and others are encouraged to recognize the family-friendly nature of the geocaching game in the choice of treasures. Geocoins and Travel Bugs® are trackable items that can be placed in a geocache in the hopes that they will have interesting travels. A virtual cache is a location without a container, and can be used for leading other geocachers to interesting spots where a container cannot be placed, for whatever reason. Letterboxing — which uses clues, rather than coordinates — is sometimes combined with geocaching.