On Memorial Day weekend, my friend Karen joined me for a yoga retreat in the Berkshires. One evening we drove downtown to get some ice cream, and on the way she asked if I’d like to help her do some geocaching while we were out.

Geocaching is basically a high-tech Hide and Seek game that involves using a handheld GPS (global positioning systems) device. You look on the Internet to see if there are any caches in your area, jot down some clues, and then use your device to find the hidden stash. When you find it, the basic rules are to take something from the cache, leave something in the cache, write about your experience in the logbook, and then put the cache back where you found it.

A GPS device can electronically determine your location – in longitude and latitude — anywhere on the planet. It is accurate to within 6-20 feet. You can program the device to lead you from one location to another. Most GPS units include compasses that indicate whether or not you’re on course.

Geocaching uses this technology just for fun, but GPS has much wider applications. It was originally designed as a navigation system for the US Armed Forces. According to the Coast Guard’s website, it involves a complex array of satellites, signals, ground stations, and data links that permit “land, sea, and airborne users to determine their three dimensional position, velocity, and time, 24 hours a day in all weather, anywhere in the world.”

Karen had already programmed her GPS device to lead us from the retreat center to the cache, only a few miles away. Since caches can only be hidden on public lands, once we got near it, it was easy to identify the conservation property where it was stashed. But then the fun began. The website had recommended a particular access to the site, but no parking was available there. We had to try another way. We found another trailhead near the parking area for the town’s DPW yard that led us straight uphill. From there, there were many trails to consider, but our GPS device made the choices rather simple.

Karen has done a lot of geocaching, so she knows what to look for. Thanks to her, we found the cache pretty quickly. I’m purposely being vague here – you’re not supposed to reveal the location of a cache in a public forum, so that other seekers won’t be robbed of the thrill of the chase.

A cache can be just a simple logbook, or a more complex treasure trove of items – some valuable, some not. The cache that Karen and I found was an old Army issue ammunition can which contained a variety of knick knacks and toys, plus some Band-Aids and ball-point pens, and quite a few batteries (life expectancy undetermined). We left a pink-haired troll doll that had been bouncing around in my car’s glove compartment for a couple of years, and took away a SpongeBob SquarePants toy that probably originated in a Happy Meal. There was a logbook to sign and also a disposable camera, with which we shot a quick portrait. Whoever’s in charge of that cache now has a silly picture of us that we hope they won’t post online.

Although it’s common to hide a cache in a “natural” environment, they are not always hidden on conservation lands. The geocaching website mentions cliffside caches accessible only to rock climbers and underwater caches found only with SCUBA gear, as well as those hidden in cities, “above and below ground, inside and outside buildings.” Once you’ve found a cache, you’re not supposed to move it (unless it asks you to), so that the person who set it up can continue to manage it from time to time.

I don’t have a GPS device myself, but I did a quick search online to see how many caches are in our area, so next time Karen comes to visit we can go find one. You can search by zip code. When I typed in “02050” for Marshfield, it came up with 83 caches within a 10-mile radius! That ought to keep us busy – especially since some of them have intriguing names such as “Whatcha Dune?,” “Who is going to pay the bill?,” “Up Cove Creek Without a Paddle,” and “A Stone’s Throw from the Blue.”

You can find out more about geocaching – and find sites in your area — by visiting For more information about GPS systems in general, visit the Coast Guard’s site at NSRWA hosts one or two geocaching events each year. Visit to find out when they are.

By Kezia Bacon-Bernstein, Correspondent
June 2005

Kezia Bacon-Bernstein’s articles appear courtesy of the North and South Rivers Watershed Association, a local non-profit organization devoted to the preservation, restoration, maintenance and conservation of the North and South Rivers and their watershed. For membership information and a copy of their latest newsletter, contact NSRWA at (781) 659-8168.