An EarthCache highlights some of the stunning rock formations along the coast of Schoodic Peninsula, the mainland portion of Acadia National Park. Credit: Aislinn Sarnacki / BDN

Reversing waterfalls, dormant volcanoes, ancient fossils and many more geological wonders in Maine can be uncovered by searching for EarthCaches. Scattered throughout the state, these outdoor destinations are part of a worldwide hunt that’s accompanied by virtual lessons, written for the everyday person.

EarthCaches are a part of geocaching, which is a popular worldwide activity that involves using GPS coordinates to hide and find caches. The traditional geocache features a container, which contains a logbook and tradeable items. EarthCaches, on the other hand, do not feature containers or any other physical item — aside from the landmarks they highlight. Essentially, they’re stops on a virtual tour.

“Often when we travel, we look at the EarthCaches in the area and go find them, whether it’s a hot spring or the top of a mountain or an old mine,” said Eric Hendrickson of Presque Isle. “It’s a unique way to explore.”

An author and retired natural science educator, Hedrickson began creating EarthCaches in Maine several years ago as a way to reach more people as an educator and contribute to geocaching, an activity he enjoys. To date, he’s created well over 100 EarthCaches throughout the state and abroad. They’re all listed on

On the website and its linked mobile app, people can sign up for a free basic membership to search for caches. The map tool includes a filter that allows you to search for certain types of caches, such as EarthCaches, traditional caches, letterboxes or mystery caches.

Because EarthCaches don’t involve hiding a container or any other physical object, their impact on the environment is minimal, especially if the EarthCache location can be viewed from a road, trail or other spot that already sees foot traffic. For this reason, EarthCaches are permitted in many places that traditional caches aren’t, such as Baxter State Park, Acadia National Park and many other conserved properties.

While EarthCaches focus on geological features, they aren’t just about rocks. EarthCaches often provide information about a location’s history or the animals and plants that live there.

To create his many EarthCaches, Hendrickson referred to information provided online by the Maine Geological Survey. He then sifted through the facts, crafting short lessons for specific locations.

“They’re typically written at an 8th grade level,” he said. “If you don’t write them that way, [] will modify them for you. They don’t want them to be too technical, so if a family goes out, mom or dad could explain to their kids what they’re seeing without getting into too much depth.”

The majority of the EarthCaches Hendrickson created can be driven to by car, though some require hiking or traveling by boat to find.

EarthCaches are usually easier to find than traditional caches because the landmarks they highlight are often large and obvious. In fact, many people find EarthCaches by simply using the map function on the mobile app — rather than using a handheld GPS device, which is needed to find exact coordinates.

Once you visit an EarthCache, you can log the find through the mobile app or website. Some EarthCache creators create a series of questions you can answer to prove you visited the spot. Photographs also serve as good proof, though they aren’t required. But many EarthCaches have no requirements for logging aside from your word that you visited the location.

“It’s basically an honor system,” Hendrickson said.

To get started, here are some outdoor recreation areas where you can find EarthCaches in Maine.

Some geocachers try to log as many cache finds as possible, earning online badges. In addition, physical EarthCache coins are awarded for finding certain EarthCaches or a series of EarthCaches.

Whatever your goal or strategy, be sure to take time at each EarthCache, reading through the lesson and inspecting the special location. That’s what the activity is all about — exploration and hands-on learning. And if you find that you truly enjoy the activity, maybe try creating your own EarthCache, adding to the worldwide hunt.

Watch more:

Aislinn Sarnacki is a Maine outdoors writer and the author of three Maine hiking guidebooks including “Family Friendly Hikes in Maine.” Find her on Twitter and Facebook @1minhikegirl. You can also...