LAKE JACKSON, Texas -- When Bill Primrose was given a Global Positioning System receiver for Christmas 2007, he didn’t know it would help him find hidden treasure.

The device has allowed Primrose to become part of a worldwide, high-tech hunt called geocaching that includes hundreds of stops in Brazoria County.

Geocaching is a game of hiding and seeking small items, Primrose said. Participants can place a geocache anywhere in the world, pinpoint its location using GPS technology and share the cache’s existence and location online, according to the Web site, Geocaching.com.

That’s how Primrose did it. The Lake Jackson resident joins thousands of geocachers logging onto the site either to enter the coordinates of a new location or to report success at finding one.

Now people find things he hides.

“I discovered it was a lot of fun searching for items,”

Primrose said. “You never know what you’ll find. Plus, I love the exercise. A lot of them have a little treasure in them, and everybody likes a treasure hunt. Geocaching is like a high-tech treasure hunt.”

The GPS gets a searcher close, but they must figure out the rest on their own.

Some treasure hiders use common items like small medicine bottles or older film canisters, while others Glitterbug, or place items in decorated containers. The “treasure” most often is the accomplishment of finding a cache, but Primrose sometimes will hide small items called “slag” with a cache to keep things interesting.

Caches range from the size of a fingernail to a 55-gallon drum, but the vast majority are microcaches, or medicine-bottle size.

“Some of them have little treasure in them nothing expensive,” he said. “Things like rubber balls, Play-Doh or a key chain.  Anything not offensive to anybody.”

Jerry Edmunson, a Dow retiree, now travels around the country in a motor home. He began geocaching in July.

Finding the general location where a cache might be hidden often is as good as finding the cache itself, Edmunson said.

“Many times the caches are hidden in very interesting places we would never visit otherwise,” he said. “It’s like one giant Easter egg hunt. The GPS receiver will get you to within 10 to 15 feet of the cache, then it’s a battle of wits between you and the person who hid the cache.”

City parks are a favorite for cachers and searchers, hobbyist John Boettiger said.

“In a section by the creek at Dunbar Park, there are three caches,” he said. “Think about a 35-millimeter film canister in a hollow tree or something to make it a little harder for you to find.”

There are about 700,000 caches in the world and more than 2,000 within a 50-mile radius of central Lake Jackson, Boettiger said.

The hobby also can be a family game, with moms, dads, grandparents and children making a geocache search part of a weekend out or a vacation, Boettiger said.

“The game is played by people who like to negotiate themselves around in the wilderness,” he said. “Some do it for the outing and some do it for the treasure hunt. It’s a neat game, and once you buy the GPS unit, it doesn’t cost anything.”

Boettiger helped form a loosely knit group of about 25 hobbyists who meet “more or less on a monthly basis” in Lake Jackson, he said. But the hunting isn’t limited to residents. Hundreds of people have been in and out of the area searching for caches.

Hurricane Ike caused a disruption in geocaching. Some sites were wiped out, were retired or removed, but that didn’t slow down the hobby.

“You just take it off the list,” he said. “It’s not so much what you find as it is about the accomplishments of doing the find.”

Common courtesy in the game is to leave a cache where it was found. But some items, named Travel Bugs or Trackables and listed on the Web, are meant to be moved.

“You take them with you between caches,” Boettiger said. “You could place a cache in Lake Jackson, and say you wanted it to go around the world, and theoretically could make it happen.”

Shirley Phillips, technology staff development director for Angleton ISD, is tracking one such cache, which has been as far as Hawaii and now is in Oregon. She plans to go to Costa Rica and will search for geocaches there.

“You could have a cache end up in Japan if you wanted it to,” she said.

In education for more than 30 years, Phillips uses her GPS and the activity with teachers and students. Although hobbyists seem to thoroughly enjoy it, geocaching isn’t all fun and games, Phillips said.

“I thought this would interest kids,” Phillips said. “I’m a firm believer in hands-on activities, learning from things lke that last longer than it would from just reading a book. It makes learning more meaningful for students.”

The process helps educators teach longitude, latitude and compass points, Phillips said.

“You’re high-tech hunting in the woods,” she said. “It can be an educational activity out in the real world. You’re out in the wild looking at trees, plants and wildlife, but to me, it’s just fun and is something families can do together. It’s a wholesome activity. I’ve met such interesting people, including other teachers and retired people.”

Geocachers use imagination when coming up with their screen names. Phillips is known as Frog Pad, Boettiger is Britt&Bess and Primrose goes by Cobra98. Other area cachers are Wildpeach and Ljtxhiker, with Edmunson using the name RVfulltime2005.

“It fits our lifestyle very well,” Edmunson said. “We usually try to combine geocaching with getting a little exercise, usually hiking or walking. We’re always in a new area, and there are lots of caches to look for while sightseeing or hiking.”

Caches are as diverse as user names, Primrose said.

“Some give more hints than others,” he said. “The hider will give some kind of hint in the title. Some will just tell you outright. Sometimes you can see them when you walk up and sometimes it takes a while.”

From one end of the county to the other, there’s no shortage of places to search, Boettiger said. But cachers operate within a code of trust: Leave only footprints and a name on the cache log.

“There are 24 city parks in Lake Jackson and there are geocaches in every park in the city,” he said.

“There are 46 caches in West Columbia inside the Hudson Woods.  It’s a friendly game. You find the log and sign it, kind of like saying you were there.”