With geocaching, you can explore hundreds of hidden places in the thousands of acres of forest in Carbon County – a kind of high-tech treasure hunt.

You use a GPS unit to find an unusual place or a location where something is hidden. If it is a box, inside there will be a log book and prizes. You sign your name to record your visit, then you take a trinket and leave a trinket of your own.

The best way to get started in geocaching is to take an introductory workshop offered by Hickory Run State Park. The 90-minute sessions are offered today at 2:30 p.m., Sunday, July 10 at 11 a.m., and Sunday, August 21 at 11 a.m. Each workshop will be held at the campground amphitheater and is limited to 20 participants.

Preregistration is required by calling 570-443-0400. Those completing the workshop may borrow a handheld GPS during the Geocaching Hiking series.

Additionally, five geocaching hikes are offered between now and Sept. 4. Preregistration is not required if you are bringing your own handheld (not automotive) GPS unit and know how to operate it. If you have taken an Introduction to Geocaching workshop, you may reserve a unit by calling 570-443-0400.

At the first workshop in the series on Friday, May 27, Megan Taylor, the Environmental Education Specialist at the Hickory Run State Park Complex explained the basics of geocaching. It begins by learning how to use a handheld Global Positioning System unit.

A handheld GPS unit is similar to an automotive GPS unit except it has a higher degree of accuracy and it does not show roads.

"An auto GPS will get you near a building," Taylor explained. "A handheld GPS unit can get you within 15 feet of a location."

The location in geocaching is a place where a cache is hidden. A cache is typically a waterproof container that holds a pad and some trinkets.

The cache is located by turning on the GPS and waiting for it to begin tracking satellites. There are about 30 orbiting the Earth and a GPS needs to track at least three, and can often track six satellite signals.

The GPS unit calculates its position by a process of trilateration by determining locations of points by the measurement of distances, using a geometry of overlapping spheres. Three satellites might register an accuracy of 100 feet, while six satellites may provide an accuracy of 15 feet.

Once the GPS has a good set of satellite signals, the unit is ready to navigate. But first, the GPS needs to know where to navigate to. Where the GPS navigates to is called a waypoint. The GPS understands a waypoint by its latitude and longitude.

At the workshop, Taylor advised the participants to input our current location, which was at the Hickory Run State Park Amphitheater: N41° 01.488 W75°41.435. The advantage of inputing your starting location is that, should you get lost in the woods, it will you help return to that waypoint.

Next, participants were given five waypoints of geocaches near the amphitheater to input into their GPS. Most were nearby. The farthest was at N41° 01.418 W75°41.492. At each location, either there was a hidden waterproof container, or a piece of information necessary to answer a question. There are over 100 geocaches in Hickory Run State Park.

To find geocaches anywhere in the world, go to geocaching.com. After a free registration to enter the site, you can input a zip code and find dozens of geocaches in that area.

Geocaching became available on May 2, 2000, when the satellite technology was opened to the public. The following day, Dave Ulmer, a computer consultant, wanted to test the accuracy by hiding a target in the woods. He called the idea the "Great American GPS Stash Hunt" and posted it in an internet GPS users' group, N 45° 17.460 W 122° 24.800, near Beavercreek, Oregon.

Soon people were searching for his stash and the geocaching phenomenon began. To avoid the negative connotations associated with the term "stash," the name was changed to geocaching.