Stamping In
In his book, Tom Sawyer, Mark Twain wrote, "There comes a time in every rightly constructed boy's life when he has a raging desire to go somewhere and dig for hidden treasure." Well, I'm a few decades past my boyhood and my 8-year-old daughter strongly objects to anything so gender specific (i.e. "What does he mean, boy's life?") But, as we walked through the woods, consulting our map, our compass, our directions and clues, and started poking under the chunk of metamorphic rock for the hidden container, thoughts of treasure were admittedly on our minds.

Letterboxes and geocaches aren't exactly buried treasures; technically, the rules say that neither is ever buried. And the treasure in each isn't in what you find at the spot marked with the X, but in the journey to get there through scenic public lands — forests, mountains, seashores. The adventure is the reason they were hidden and the reason why you are seeking.

Letterboxing began in the mid-1800s in what is now Dartmoor National Park in England's Devonshire region. Walking the moors wasn't for everyone. James Perrott had been out on a difficult 15-mile hike and had reached a desolate place called Cranmere Pool. Before he left, Perrott hid a glass jar inside a pile of rocks next to Cranmere Pool. Inside the glass jar, he placed his business card — and an invitation for other hardy hikers to leave their cards to prove that they too had visited the same hard-to-reach spot.

Over the next hundred years, a handful of other letterboxes were established in other, out-of-the-way places in the park. Clues to their locations were passed from hiker to hiker. But around 20 years ago, letterboxes started being hidden in more easily accessible locations. Soon, the number of people hiding and seeking letterboxes in Dartmoor had skyrocketed. Business cards gave way to rubber stamps, stamp pads, and log books. There are now over 10,000 letterboxes hidden in Dartmoor — ten times the incredible number of Stone Age monuments in the park.

An American Twist
The first letterbox my daughter and I went looking for wasn't there. It happens. However, it was a terrific hike to a part of an Audubon sanctuary where we had never gone before. A week later we tried again. The clues my daughter and I followed were fairly straightforward. Follow the path until it bends back. Find the S-shaped tree. Walk 5 paces NW and turn E. Look under the slab of stone. Sure enough, in a crevice beneath the rock, we found the container that held the stamp, pad, and logbook.

Letterboxing in the United States is a recent development. An article on the Dartmoor letterboxes appeared in the April 1998 issue of Smithsonian. Soon letterboxes were popping up all over North America. Best estimates suggest that there are already close to 2000 letterboxes hidden in the United States.

For the most part, the idea of letterboxing didn't change when it crossed the Atlantic. Letterboxes are still hidden on public lands and in scenic or remote places hikers want to share with other hikers. The letterbox itself is a waterproof container in which the box owner has placed a logbook, a rubber stamp (often carved), and a stamp pad. The letterbox seeker carries his own personal logbook, his personal stamp, and a stamp pad. When the seeker finds the letterbox, he stamps his logbook with the box's stamp and stamps the box's logbook with his stamp. That way, the letterbox has a record of all the adventurous souls who have found it. And the seeker's logbook records all the letterboxes he has found.

Not all clues to letterbox locations are easy or straightforward. Some people post clues written as stories or poems. Sometimes clues are in code that must be deciphered. Other times you might encounter riddles or even math problems. And then there are the mystery boxes, where you start out knowing only which state or county in which the letterbox is hidden. Typically American, there are even urban mystery letterboxes. For example, there's the "Ace of Fun" letterbox hidden in Portland, Oregon. The only clues provided are: Unscramble its name and you will learn the home of this mystery box. It lives between a tempest of tutus and a plethora of pigments. Not so easy, is it?

A Great, Black Beast
If Dartmoor rings a bell with you, it should. Dartmoor is the setting of the famous Sherlock Holmes story, "The Hound of the Baskervilles." (And if you haven't read it, you can read it online!) Author Arthur Conan Doyle was inspired by the creepy, empty moors of this area of England's Devonshire and by the local, centuries-old tales of demon hounds leading villagers to their doom. Conan Doyle changed many of the location names in his story — and created a Baskerville Hall where no real castle exists — but many other features in the story, from the Neolithic huts to Dartmoor Prison, are still there today.

In the story, Sir Charles Baskerville is said to have been frightened to death by the "hell hound." Interestingly enough, researchers recently published a paper in which they say that it is in fact possible to die of fright.

More Links
Getting started with letterboxing can be as simple as visiting the Letterboxing North America Web site. Here you will find tips for beginners and clues to letterboxes hidden throughout the United States and Canada.

The serious letterboxer needs a personal, one-of-a-kind rubber stamp to stamp the letterbox logbooks. Some people make their own stamps by carving erasers.

For an outdoor adventure like letterboxing or geocaching, a few orienteering skills might come in handy. To review map and compass skills, visit this USGS site.

Caching In
Like the letterbox, the geocache is a hidden container — something as small as a film canister or as large as a 5-gallon drum. But instead of containing a stamp and pad, the geocache contains what some might facetiously call treasure, but what others might more accurately call... stuff.

The person who originally hides the geocache fills it with a logbook and an unpredictable selection of goodies. For example, a geocache might originally contain a bucket of plastic monkeys and a handful of buttons that say "I Found the Purple Porcupine Geocache!" However, that doesn't mean that the contents will remain the same. Geocache etiquette says that, when you find the geocache, you are allowed to take something from the cache as long as you leave something else of your own behind. Inside a well-frequented geocache you might find anything from Pokémon cards to refrigerator magnets, CDs to foreign coins, yo-yos to keychains. Many caches include a disposable camera so that the finder can take his or her own picture at the cache. The cache owner later retrieves the camera, develops the film, and then either leaves the photos in the cache or puts them on the cache Web site.

Geocaching is an activity that has taken off at an even faster pace than letterboxing. The first geocache was hidden on May 3, 2000 and found several times within days. Now, according to the official Geocaching Web site, there are close to 15,000 caches hidden in 119 countries. Perhaps it is this explosive growth that has led the US National Park Service and some state parks to ban placement of caches on park property.

Seek Safely
Like any outdoor sport, letterboxing and geocaching can be risky if not done properly. The person who places a letterbox or geocache won't purposely place it anywhere where it will be a risk to the seeker. However, be sensible! Be prepared for the hike you're going on. Don't go alone. And kids should never go hunting unsupervised.

Zeroing in on the Loot
Geocaching is like letterboxing's high-tech first cousin. There aren't clues to finding a geocache the way there are with letterboxes. Instead, the person who hides the geocache actually posts the cache's exact latitude and longitude coordinates. Finding a geocache requires the use of a handheld GPS (Global Positioning System) receiver. The GPS is able to pinpoint its own latitude and longitude position on Earth to an accuracy of within 20 feet. The idea of geocaching is to "follow" the GPS to the exact location of the hidden cache.

The Global Positioning System (GPS) is a group of 24 evenly-spaced satellites in Earth orbit. With 24 satellites, four to eight satellites are always above the horizon, no matter where you are. A GPS receiver contains information about where each satellite should be at a given time. The GPS receiver needs to pick up signals from at least four satellites so that it can determine its exact latitude and longitude. By calculating very exact distances from itself to each satellite, the GPS receiver is able to triangulate its position in the same way seismologists are able to find an earthquake's epicenter using distance data from three seismograph stations.

Perhaps we shouldn't need an excuse to seek out beautiful, seldom explored, often overlooked spots in our towns, suburbs, and countrysides. However, if the next time you ask yourself whether you should go for a hike or play Nintendo, listen to the little voice inside your head. That voice might just be saying, "I know where there's a logbook waiting to be stamped" or "You know, I bet there's a hidden plastic monkey out there with our name on it!"

— by Andrew Amster