Via The Geocaching Blog

When geocachers step outside with a GPS-enabled device, they’re tapping into decades of brilliant science and mathematics that make those coordinates possible. Behind every successful find stands a brilliant mathematician whose work helped make modern GPS possible: Dr. Gladys West.

Gladys West’s groundbreaking work focused on solving a deceptively complex problem: determining the Earth’s precise shape.

In the 1960s and 1970s, West helped process vast amounts of satellite data to model Earth’s geoid. Because satellites orbit based on Earth’s gravitational field, understanding this shape was essential for calculating accurate positions on the planet’s surface. West programmed early supercomputers to analyze oceanographic and satellite measurements, producing increasingly precise models that became foundational to the development of the Global Positioning System (GPS). When GPS satellites were later deployed, they relied on these accurate Earth models to translate satellite signals into the exact coordinates we use today for navigation, mapping, and location-based technologies.

Geocaching is built on a beautifully simple idea: use GPS coordinates to find hidden treasures around the world, but the magic behind those coordinates depends on an incredibly sophisticated system of satellites, timing signals, and Earth models.

Thank you, Gladys West, for advancing geodesy and satellite modeling, making the precision of geocaching possible!

Celebrate Blue Switch Day 2026 by hiding a geocache, and earn your Blue Switch Day 2026 hider souvenir.

Blue Switch Day 2026 hider:

• To earn this souvenir, geocachers must have a non-Event geocache published between May 1 and 31, 2026.
  • Any non-Event geocache type (excluding Adventure Lab®) counts, as long as it is published between May 1 and May 31.
  • Remember that review times may vary! A geocaching community volunteer will typically begin reviewing your geocache within 7 days. We recommend submitting your cache for publication at least a week before the deadline. Learn more about the cache review process in our Help Center.

How will you celebrate Blue Switch Day this year?

Via The Geocaching Blog

General Notice about the Alaska State Parks permit status:  

By Mike Malvick (GreatlandReviewer/ladybugkids)

scobey, archived

John Leon Scoblic (aka scobey), age 76, of Anchorage, Alaska, passed away on Dec. 25, 2025, at home after a long and valiant battlewith   cancer.  His full obituary was published in the Anchorage Daily News on January 4, 2026.  His funeral was held at St. Elizabeth Ann Seton Catholic Church on January 10, 2026, and he was interred at Fort Richardson National Cemetery in April, 2026.

Scobey was a fixture of geocaching in southcentral Alaska for six years beginning in 2004, before his health and other factors limited his ability to get outside and enjoy one of his favorite pastimes.  Despite being active for a relatively short stint, his geocaching legacy lives on through his caches and GeocacheAlaska!

Scobey’s family engaged in geocaching and his wife Linda, and his daughter, Alicia (aka Geminigirl) often accompanied him on his caching outings.  His adult son, John, also tagged along when scobey visited his family in Ketchikan, Alaska, and scobey commemorated the birth of his second grandson, Jonathan, with Johnathan’s Cache.  His beloved bichon frise dog, “Beamer,” was rarely far from scobey.

Scobey has numerous notable caching firsts in Alaska:

• First Challenge Cache: Alaska Borough and Census Challenge (GCYPMN)
• First GeocacheAlaska! website
• Launched the GeocacheAlaska! Forums
• Founding Member of GeocacheAlaska!
• First Alaskan cacher pathtag (scobey)
• First Alaskan dog pathtag (Beamer)
• First Alaskan to break a bone while caching, which led to the production of the “Geocacher Needs Maintenance” geocoin and pin as a show of community support for his quick recovery. Be sure to click the link for the full story in the geocaching.com forums. 
• First or second nano cache placed (I was unable to confirm whether the community gets to blame scobey or oleruns for this)

In addition to geocaching, scobey also enjoyed hunting for benchmarks, and frequently placed caches near them to highlight their presence and encourage other cachers to log them both at geocaching.com and the United States Geological Society (USGS) sites.  He was regularly found scouring an area with a metal detector and a shovel, searching for “marks” that urban sprawl had covered.  

Scobey enjoyed combining traveling with caching and attended the third annual Geocoinfest (2007) in Temecula, California, and cached his way through palm tree oases, slot canyons, and nearly got arrested by tribal police at the edge of a casino parking lot while hunting for a cache that was placed without tribal permission.  His southernmost find is in Ecuador and his easternmost find is in the Philippines.  He also cached in Dubai, United Arab Emirates. 

Scobey was always loyal to technology and enjoyed razzing anyone who used a Magellan rather than a Garmin GPSr.  He also applied technology to his caches, including the still active Radio Days (GC1JWBZ) multicache.  Scobey enjoyed creating series of caches to reveal his love of:

• Puzzle caches (221B Baker Street (GC22A6J, GC10VPD, GC119Z7, GC11FDP))
• Benchmarks (GC15M5K, GC3N67V, GC13DTA, GC1250N, GC12CV6, GC14T2F)
• Cavemen (GC149HA, GC14AF9, GC16CRM)
• EarthCaches (GC124ND, GC12914, GC12CV6, GC14T2F)
• and, the Medical Establishment, including doctors and nurses who helped him battle his ailments (GC116T5, GCXV1G, GCZ76D, GCYM6F, GC14T65)

Scobey was a complex, talented, and generous person who brought his varied interests to the local caching community and we are better for it.  He is missed.

Note:  A geo-memorial celebration of caching, “Scobey the Puzzlemeister” (GCBN9ME) is scheduled for 4:00-5:30 p.m. on Saturday, May 2, at Russian Jack Park North Pavilion.

By Mike Malvick (Greatland Reviewer/ladybugkids)

The following is adapted from a Geocaching.com Forum post written by Community Volunteer Reviewer Keystone nearly twenty years ago in June 2006, with minor modifications based upon Guideline changes and conditions specific to Alaska.  Keystone has reviewed cache pages for Pennsylvania and Ohio since 2003.

When reviewing a new cache page submission, the Community Volunteer Reviewer (Reviewer) starts with the proposition that the hider of the cache is responsible for obtaining “adequate permission.” Note that it says “adequate permission” in the Guidelines — NOT just “permission.” The Reviewer relies upon cache owners to think about this issue and make a determination about what permission is necessary. In submitting a cache page, the geocacher assures the listing service (Groundspeak/Geocaching HQ/Geocaching.com) that adequate permission has been obtained, and the listing service assumes that this is the case. As a listing service, Geocaching.com is not a guarantor of the proposition that every cache is placed with permission. But sometimes there are circumstances why this assumption ought to be questioned. Here are some of them:

1. When a landowner/land manager such as a park system (Alaska State Parks is GeocacheAlaska!’s primary permit issuer) or a private land conservancy trust has a published geocaching policy that Groundspeak is aware of, then the Reviewer will ask the cache owner about compliance with that policy. Knowing of the policy’s existence, it is not appropriate to blindly assume compliance with the policy if no mention is made of this on the cache page. So the Reviewer will ask whether a required permit has been obtained or, in the case of a blanket permit such as with Alaska State Parks, if the stipulations of the permit are met.  In some cases, such as National Parks, National Wildlife Refuges, and National Monuments, which generally do not have an open geocaching policy, we will ask whether the hider obtained explicit permission from the Land Manager or their designee. 
2. When a cache is hidden on land that is obviously private, like someone’s back yard, it is unwise to blindly assume permission. Usually permission is stated or implied on the cache page (“this cache is hidden in our front yard — please, no night caching”). If it isn’t, the reviewer may ask about it. The guidelines require permission for caches hidden on private property. There’s even a specific sentence about never ignoring a “no trespassing” sign.
3. Some locations are so sensitive in nature that it is unwise to assume that permission has been obtained, so specific listing guidelines have been adopted to guard against placements in those areas. Examples include airports, government buildings, school yards, dams, highway bridges, and utility infrastructure. If the reviewer sees a cache in one of these locations, they will challenge the assumption of adequate permission by reference to these specific guidelines.

In most other cases — ranging from suburban parks to shopping centers to little free libraries — it is up to the cache owner to determine what constitutes “adequate permission.” One cache owner might conclude that no formal permission at all is needed for a particular spot, while another will obtain written or oral permission for a different cache location because their instinct tells them that permission is a good idea. If the cache owner arrives at an unwarranted conclusion, the listing service will react to questions about permission. First, if a land owner/land manager requests removal of a cache placed without permission, Groundspeak’s policy is to archive the cache unless and until the hider is able to straighten things out and provide an explanation of clear permission. Second, if another geocacher sees a cache location which causes them to have doubts about permission, they are welcome to raise their concern with the cache owner. If that is not productive, the geocacher may contact  Groundspeak via the Contact Us link, contact the local Reviewer, or write a “Reviewer attention requested” log on the cache page. The system is thus largely self-policing in this majority of circumstances.

By Louise Kempker (freeweez)

It’s Spring—and for Geocachers–that means you are now able to search & find those smileys that may have been hidden all winter long!

The German Exchange Cache – GCAGN3J  –  is waiting just for YOU!  There are German cachers awaiting a ‘partner’ here in the Anchorage area—so please head on over and find this Multi with a partner.  You find the first stage in Anchorage (easy PNG) –and send the coordinates inside the container to your German ‘partner”—and they will send Final coordinates back  to you.  The final is a short walk in Kincaid Park–and should be pretty uncovered with snow by now! Cache On—and venture forth into New Country-to Country caching!  

Via: The Geocaching Blog

When you see a blue question mark on the map, do you feel curious—or confused? Mystery Caches—also known as Puzzle Caches—can be intimidating. Some puzzles involve codes or ciphers. Others require solving math problems, answering questions, or reviewing the cache page for hidden clues.

Solving puzzle caches takes patience, attention to detail, and a willingness to try different approaches. We asked geocachers to share their best advice for getting started.

Note: Some of the responses have been edited for clarity and brevity.

• “You are trying to find final coordinates. Knowing what you need in the end can help to get you thinking in the right direction and give clues to potential pieces of information.” – emilierene
• “First, put yourself in the creator’s shoes. Consider the meaning of the title and why it was placed here. Don’t overlook even the smallest hints.” – GC Gakujgn
• “Read, read, read… and did I say ‘read again’? Even I get caught up in the moment and adrenaline rush and still sometimes miss essential details, especially when you have to do translations.” – FindingNiels
• “We hold occasional puzzle-solving events. Everyone brings a list of puzzles they want help with. We take turns working on the puzzles together.” – Marguerite B.
• “Gradually accumulate skills and learn from others. Use the D-rating as a guide—D1 and D2 are usually suitable for beginners. Tackling a D4–D5 right away will probably discourage you and make you give up.” – Thomas T.
• “With puzzles that require full coordinates, look for patterns that produce the first part you already know. For example, if I’m solving locally and expect South 30°, I’ll look for ways the puzzle could result in S30 or ‘South Three Zero.’ Solving a puzzle that has stumped me for months is honestly one of the most satisfying things I have ever experienced. Sometimes it just takes the right mood, location, or moment for your brain to find the key to start unravelling it, even if you’ve stared at it for many hours previously.” – Nicole S.
• “I like to print out puzzles so I can make notes. When I’m stuck, I reach out to previous finders or the CO. I also bring puzzles to events to see if others have insight, and keep some in a folder to work on when the weather isn’t caching-friendly.” – Laura L.
• “Attend events and ask questions. Or check if there’s a puzzle group in your area (don’t forget online groups. We have two very active online puzzle-solving groups based in Victoria, Australia). If there are no groups, consider a puzzle-solving event. All the geocachers I know generally want to help out or learn!” – LetThemEatCache
• “There are so many aspects to geocaching; find the ones that bring you joy, and leave the rest for others to enjoy. If puzzles are more frustrating than joyful, put them aside. That being said, the more you work on them, the better you will get, which can bring you joy.” – gsmX2

Here are some online resources that may give you more tricks to try:

• Geocaching Toolbox
• My Geocaching Profile
• There are many more! Do an online search for “geocaching puzzle solving tools.”

Looking for more guidance? How to Puzzle Cache (Second Edition) by Cully Long—featuring over 300 pages of lessons, tips, and step-by-step techniques for tackling everything from codes and ciphers to math, music, and more—is available at Shop Geocaching

Via The Geocaching Blog

Whether you’re out on a hike or visiting a local park, sometimes you come across a spot and think, “That would be a great place for a cache.”

With the latest Geocaching® app release (version 10.7.0+), you can now record a hiding spot, add cache details, and submit a Traditional Cache for review—all from the mobile app!

Earlier this year we introduced the coordinate collector to help players capture accurate coordinates in the field. Now we’re taking the next step toward a more mobile-friendly hiding experience by bringing key parts of the Traditional Cache hiding process into the Geocaching® app.

Get started from the Hides tab

To begin, open the Hides tab in the app and tap the + in the upper right corner. Select ‘Geocache,’ then Traditional Cache.

Currently, Traditional is the only cache type that can be created, edited, and submitted from the app. Selecting another cache type will open a mobile web browser so you can continue creating the listing on Geocaching.com.

From the app, you can now:

• Name your geocache
• On the Location screen, enter coordinates or tap the bookmark icon to collect coordinates or choose saved coordinates
• Set difficulty and terrain ratings, and size
• Add cache details like the description and hint
• Add attributes to help future finders know what to expect
• Add and describe a helpful image (e.g. location or spoiler)
• Make sure your cache container is placed and ready to be found
• Submit your cache for review by a community volunteer reviewer

If you still need to place the container or want more time to add details, you can save the listing and finish it later. Edit your Traditional Cache in the app (Hides tab > Unpublished) or from your cache owner dashboard on Geocaching.com.

Ready to hide? Visit Shop Geocaching to browse cache containers in a variety of sizes, colors, and shapes.

NOTE: Creating a cache listing does not reserve or guarantee a location for your cache. To learn more about hiding guidelines, visit the Help Center.

By Mike Malvick (Greatland Reviewer / Ladybugkids)

• Ideally, caches should not be disabled long term. The Hiding Guidelines state “A cache page can stay disabled for a reasonable amount of time – generally up to four weeks.”  
• If the cache owner is active and responsive, it is the Reviewer’s discretion to decide what the maximum length of time the cache remains disabled. For inactive or unresponsive cache owners, the 4 week guidance should be applied.  Reviewer discretion may also be applied for caches in remote locations (mountains, coastal islands, etc.) where seasonal conditions are a factor.