Cairn is an outdoor safety app that makes it easy to find and collect cell coverage in the wilderness and keep loved ones up to date. Cairn’s mission is simple: Keep people safer in the outdoors. We think that getting outside is essential for the mind and body but that adventuring comes with inherent risks. With Cairn you can go more places knowing that you’ll be able to make an emergency call. Feel more comfortable hiking solo. Because getting to the top is optional; getting home is mandatory.


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  • Crowdsourced cell coverage maps

  • Safety notifications sent at the start and end of each trip with an automatic overdue notification

  • Live location tracking, including phone battery state and cell coverage at each point

  • ETA, distance and elevation details for thousands of routes and summits worldwide.

  • Detailed, downloadable maps optimized for the outdoors

iOS-only features

  • Stat tracking, for recording and saving trails

  • Saved trail export as .gpx

  • Tracking settings that allow for control of phone battery consumption

  • I’m OK messaging; Cairn keeps trying to send until successful

  • Speed and activity settings for customized ETA stats. E.g. for snow travel or trail running.

    Android-only features

  • Pending check in; Cairn automatically ends your trip when you regain cell service

  • Filter by carrier; see cell coverage data only for carriers of interest


  • Cairn users have gathered millions of points of cell coverage on trails all over the world

  • Cell coverage data is available in most US national parks, in over 90 countries, and along the entire Pacific Crest Trail

  • 4,000+ safety notifications sent per month

  • Useful for hikers, climbers, runners, backpackers, cyclists, backcountry skiers, boaters, anglers, and more


“The feeling of relief, how grateful I was that we had the app, is something that will stick with me for a while. I’m a true believer in this app now and will continue to use it on every trip I take.”  — Jake Tonnessen (FACEBOOK)

“In southern Oregon I was able to help out some other hikers who needed to call their pick up but couldn’t find cell coverage.”
Daniel Briggs (ITUNES) 

“Love your app and use it almost daily when I go out with my dog.”
June Mansfield (EMAIL)

“We have been using this app in Puerto Rico to help map all the science studies we have been doing in the rainforests above caguas after the hurricane. It is too good to be true.”
@frohkid (ITUNES) 

“Love that every hike contributes info other hikers can use!”
Bird9876 (ITUNES) 

Cairn in the news

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