At midnight on May 2, 2000, twenty-four satellites around the world processed their new orders, and instantly, the accuracy of GPS technology drastically improved. For GPS enthusiasts, this was a cause for celebration, while Internet newsgroups were suddenly exploding with ideas about how the technology could be used.

The very next day, Dave Ulmer, a computer consultant, wanted to test the accuracy by hiding a navigational target in the woods. He called the idea the "Great American GPS Stash Hunt" and posted it in an internet GPS users' group. His idea was to hide a container in the woods and note the coordinates with a GPS unit. The finder would then have to locate the container with only the use of his or her GPS receiver. The rules for the finder were simple: "Take some stuff, leave some stuff."

Ulmer placed his own container, a black bucket, in the woods near Beavercreek, Oregon. Along with a logbook and pencil, he left items including videos, books, software and a slingshot. He shared the waypoint of his stash with the online community on sci.geo.satellite-nav. Within three days, more people read about his stash on the Internet, used their own GPS receivers to find the container, and shared their experiences online.

Within the first month, Mike Teague, the first person to find Ulmer's stash, began gathering the online posts of coordinates around the world and documenting them on his personal home page. The "GPS Stash Hunt" mailing list was created to discuss the emerging activity. Names were tossed around to replace the name stash due to the negative connotations of that name – one name was "geocaching.”

Today, geocaching is a real-world, outdoor treasure hunting game using GPS-enabled devices. Participants navigate to a specific set of GPS coordinates and then attempt to find the geocache (container) hidden at that location. The combination of the earth and technology made geocaching an appropriate term for the activity.

The Northwest Herald recently reported that Illinois resident Nathaniel Spiers attended a geocache rally in Crystal Lake months after receiving a GPS device in 2009 as a Christmas present. The rally at Veteran Acres Park, organized by the McHenry County Conservation District, would plant the seed for the 18-year-old’s passion for geocaching explorations.

 “You can go out hiking down the woods,” Spiers said. “They’re everywhere: forest preserves, downtown in the city.”

Spiers is among the growing number of geocachers worldwide who interact online at www.geocaching.com or through smaller, individualized sites, including Spiers’ site, hikern.uni.me. There, geocachers look up cache listings and pick a cache by plugging its navigational coordinates into a GPS device to begin the search, and afterward, geocachers return to the Website to log their find. Spiers feels that geochaching gives him an added sense of purpose while he’s enjoying the outdoors and gives him a way to network with people around the world.

How is the game played?

• Register for a free Basic Membership.
• Visit the "Hide & Seek a Cache" page.
• Enter your postal code and click "search."
• Choose any geocache from the list and click on its name.
• Enter the coordinates of the geocache into your GPS Device.
• Use your GPS device to assist you in finding the hidden geocache.
• Sign the logbook and return the geocache to its original location.
• Share your geocaching stories and photos online.

What are the rules?

• If you take something from the geocache, leave something of equal or greater value.
• Write about your find in the cache logbook.
• Log your experience.

“There are also unknown, mystery caches where you have to solve puzzles in order to get the coordinates,” Spiers said. “I personally own 13 caches. For one of my unknowns, I have a puzzle, a math problem that you need to solve to find the coordinates. So you’ve got to find the answer to the math problem, which gives you the numbers to plug in as coordinates in your GPS.”

The county conservation district in Spiers’s home town in Illinois began allowing geocaching at its parks in 2008 when it was proposed by a resident, according to Stephanie Michael, geocaching program coordinator at the county conservation district. Now, there are 66 caches hidden throughout the county parks system. From the district’s perspective, the hobby is just one way to promote the natural resources and encourage the public to visit their local parks. Michael said geocaching has become a popular way for families to spend time together as well as for individual geocachers to earn “bragging rights.”

 “Cache Your Way Across McHenry County,” the district’s next geocaching program, designed especially for beginners, is scheduled to run this fall in McHenry County, Illinois from August to November.