You could see it in the license plates of the vehicles arriving at Carnation’s Remlinger Farms. Plates from everywhere from Tennessee to Canada’s Northwest Territories were evident in the hundreds of cars, conveying an estimated 5,000 participants to Geowoodstock VIII, a global convention of geocachers.

In white paint, one SUV’s back window proclaimed “GWVIII or bust!”

Geocaching is a growing hobby in which hikers use global positioning devices to hide and track down hidden packages.

“It’s basically going out for a hike and treasure hunt at the same time,” said Brednan Vanous of Seattle, who attended with his wife Cindy.

Cachers use call signs and place their own treasures in their caches. New caches are being developed all the time.

“They’re definitely in your own neighborhood,” said Geowoodstock attendee Mike Robinson, who came from Chattanooga, Tenn., to take part in the Carnation convention. Some caches are on downtown streets. Others require a 30-mile bushwack, Robinson said.

Since its inception, Geowoodstock has become something of a happening, Robinson said. Caches enjoy conversing about others with their hobby. Vendors also came to share products. Live music, scavenger hunts and games filled Remlinger’s Indian Creek field.

Geowoodstock continues through Sunday, July 4. Some cachers planned to attend Carnation’s Fourth of July celebration.