Gear Review – Guthook AT Hiker App

There are many choices of navigation tools for hiking the AT; gps, maps, various trail companions and guidebooks, and, of course, there’s always the white blazes. Some say the Trail is so well marked and traveled, you only need to know how far to the next water source, shelter, or what’s available in that town yonder over there. Maybe so. I do know that you don’t ever need any navigation tool until you need it (I don’t believe Yogi Berra said this).

The AT Hiker app was developed by Ryan Linn. Since Ryan’s Trail name is Guthook, the app is also known as the Guthook’s AT Hiker app (referred to from now on as Guthook). I came across Guthook about a year ago in a discussion about navigation tools on the hiking forum Since I would be carrying a map & compass and AWOL’s printed AT Guide, I wasn’t sure I needed anything else. But, not one to discount a cool gadget/app thingy, I checked it out. I downloaded the free Demo (The Amicalola Falls Approach Trail) and thought it was pretty cool. So, I bought the whole thing.

Following are my impressions.


At the time of this writing, Guthook can be purchased in 9 individual trail sections at $8.99 each, or all parts in one bundle for $59.99.

The app can be downloaded onto either an iPhone or Android. I have an iPhone, so this review will be on the iPhone app, only. You can download the iPhone app at the Apple store and the Android at Google play or, you can go here.

The app has over 3,500 waypoints such as shelters, tent sites, water sources (along with historical dependability), trail junctions, road crossings, peaks, views, etc. Each waypoint has a separate page with supporting data such as elevation, and distance to next shelter/water source (NOBO and SOBO).

The base app is about 15 MB, but that’s mostly an empty shell with no trail info. Each trail section is broken down into the basic data (waypoints and track line), which is about 1 MB per trail section, then photos and offline maps. Each section’s photo set is in the range of 50 to 75 MB, and each offline map set is between 40 and 80 MB. You can download or delete offline maps and photo sets as you please, so basically the minimum size of the app, if you purchase every trail section, is around 25 MB, and the maximum size if you download all of the photos and all of the maps without deleting them to save space is around 2.5 GB. I have them all.

The bottom toolbar lists options of Map, Elevation, Info, Data Book, and Settings.


The app organizes the AT in 9 geographic trail sections, including the Approach Trail. The base map options include road map, satellite or a combination. The base map is what you see beneath the line of the trail and the waypoints and is the same as the Maps app from Apple. It downloads pieces of the map as you scroll around. The problem is, it isn’t very detailed and it won’t load if you don’t have an internet connection – could be a problem. So, to see topographic maps without an internet connection, you need to download the ‘offline’ map set(s) before you leave town.

Touch the foot print icon (lower right of the map) to select a different trail section, or touch the map icon to change the map terrain.

AT Hiker Mao Formats

AT Hiker Map Formats

There are four offline download options for map terrain from USGS Topo to Google Streets. Once they’re downloaded, you can select one to display on the map. Also, in smart phone fashion, you can zoom in and out of the map as needed. Touch on a waypoint, and it brings up a box with the name and the distance from the starting terminus you selected (Springer or Katahdin) in miles or kilometers. A touch of the box takes you to the Data Book page for that waypoint.

NOTE: Ryan tells me the interface for downloading the maps will change quite a bit with the next app update.




Tap a waypoint and it brings up it’s name and distance from the terminus.

The elevation is as helpful as all elevation profiles are, so nothing new here. However, if the coming day’s climb has you down, just zoom out on the elevation page and, whala,  problem solved. If only it were that easy!

With the gps function on, you can find your relative position to the trail in terms of elevation. This was helpful to me as I wondered how much farther to the top of Big Cedar Mountain. Ugh!!

Tap the Waypoint bubble and it opens the waypoint's Data Book page.

Tap the Waypoint bubble and it opens the waypoint’s Data Book page.



The info function acts as a sort of trail register where users can post updates as they move down the Trail. I can see this as a great way to keep in touch with or track down hiking partners.

It also allows hikers to give updates on availability of water, bear activity, privy status, views, or what have you.

NOTE: If you’re headed to Hawk Mountain Shelter, you might want to take a trowel. Just say’in.


Data Book

Choose a waypoint by feature, or you can select all.

Choose a waypoint by feature, or you can select all.

As you can see from my iPhone grab at right, the Data Book is organized according to features. You can find a waypoint by feature or select all to list all of the features in the section.

If you touch an icon on the map or elevation pages, it automatically opens the Data Book page for the waypoint. Or, if you want to search for a particular waypoint, you can search within one of the feature classifications or, you can select all features and it lists them according to mileage from Springer (or Katahdin).


Selecting All Waypoints lists the features by distance from the terminus.


Settings page

Settings page


In the settings section (right), the map and waypoints can be oriented according to north or south bound with a flip of a switch.


GPS Function (This is so awesome, I can’t stand it!)

All smartphones have what is called Assisted GPS, which means they have a true GPS receiver, and they also use cell tower triangulation when possible to increase accuracy and speed up the time it takes to get a lock on your location. As of iOS 8.3, the GPS still works in Airplane Mode. If you turn on Airplane Mode, the cellular part of the phone is disabled and the phone relies solely on GPS at that point. So, it is a true GPS.

Good news for those suffering from data charges. Using the GPS to find your location results in no data draw on your phone. Even when using Assisted GPS with the cell towers, there is no data draw to find your location. What an app does after it finds your location could use data, but Guthook’s apps don’t do anything with your location that triggers any data usage. That said, no app can use your data while you’re in Airplane Mode, so Airplane Mode is a good safeguard against data usage. (You will want to keep your phone in airplane mode, anyway, otherwise your phone will continue to look for a tower and kill your battery.)

Smartphone GPS’s are pretty accurate. Sometimes it takes a little longer to get a fix on your location than other times, but once you have your location it’s generally quite good. Ryan tests this fairly often by carrying any combination of two iPhones (his old one and his current one) with two handheld GPS units and tracks his hikes. He says there has never been a major discrepancy between the readings of each. The major difference is mainly the time it takes to get a lock on your location after having the GPS turned off for several hours. When turning a GPS on after a short period of time, there’s generally a short delay before it finds you. The longer it has been turned off, the more chance there is that it will take a minute or longer to lock on.

I find this true for my car gps. If I turn it off in Kansas and then back on in Wisconsin, takes some time to figure it out.

That said, one concern I have is the affect of hiking in the green tunnel. Guthook tells me the accuracy of the GPS can be affected by tree cover, but usually it’s not. The biggest problems will come from being in deep valleys and canyons, or being under dense tree cover while it’s raining heavily. Also, if you’re close to either the South Pole or North Pole, that will also affect things. Uhm, probably not an issue.

Trial Run

My first trial runs were months before I did my section hike. I used it, and still do, as I virtual hike or read the various AT hiking travelogues. The elevation profile and maps helped me be a part of the story and better track where the author was in terms of the overall trail and the elevation changes. It was fun to use the Data Book to look at a picture of a view, shelter, or stream mentioned in the book. It really helped the reading experience come alive. It’s also fun to use the app as I read the posts from hikers on

The real test, however, was when I took it on my Springer-Neel’s Gap section hike. I hiked off and on with a bubble of about 4 or 5 people. A few times we got confused (or concerned) about where we were. ALWAYS, they would ask me to check Guthook. Pull out the phone, touch the GPS button and, bingo, we are here. The GPS bugger also lights up on the elevation profile, which I used more than a couple times climbing Big Cedar Mountain – ugh!

The Good and the Not-so-Good

The Good

  • Zero added weight – if you already intend on bringing a smart phone.
  • Pictures of locations – At first blush, it seems this would only be helpful for virtual hiking. But, it’s helpful in verifying that this creek is actually that creek on the map.
  • Descriptions – This is helpful to get more information about shelters (how many they sleep) and capacity/amenities at each shelter. It will also give an estimated tent capacity, too.
  • To/from distances – This is a help in deciding if you want to move on to the next waypoint.
  • Active feedback from other hikers – Although sporadic, I can see this as a help, particularly in times of scarce water.
  • Excellent support – Recently, I upgraded to an iPhone 6s. Sunday evening, after downloading the app from my cloud, I noticed I was missing the photographs from a few of the parts. It was 7PM when I emailed Ryan about the issue, hoping for a response sometime the next day. Thirty minutes later, I got an email response and we worked through the issue – Bada-Bing-Bada-Boom! I’m still blown away. It was as if Ryan was glad I contacted him on a Sunday evening. In the Total Quality Management world, they call this “knock your sox off customer service.”
  • GPS – Provides near exact location on the trail map and elevation through gps function – There was one point on my section hike where the trail seemingly disappeared. The group of us looked all around for it, but couldn’t find it. Everyone said, “Hey, check your phone.” I opened the app, zoomed in, and found where we were relative to the Trail. The Trail had taken an improbable left turn up and over an illogical 3-foot ledge.
  • Not just for hikers – As I said, this really helped me bring my favorite Trail books and journals come to life.

The Not-so-Good

  • It’s still electronics on the Trail – If your phone is dead, you’re out of luck. The cell portion of my iPhone died on my section hike, but the app and gps function continued to work. For that reason, I wouldn’t depend on Guthook as my sole means for navigation just as I wouldn’t depend on a $500 GPS.
  • Not everything plus the kitchen sink – I don’t consider this as a deterrent to buying the app, but I will still carry a Trail Guide to use with this for more information on town services, etc.


Each of the available resources (map, guide book, and Guthook) have a place on an AT thruhike. I will be looking forward to using Guthook as part of my resource toolkit on my upcoming thru hike.

Ryan Linn tells me there’s an update coming soon, which will change a lot of how the app looks and with some additional features, which I am really looking forward to.

Guthook also has Guides for other Trails.


I would thank Ryan Linn for his patience and thoroughness  in answering questions from a not-all-that-literate techy (being me). I am continually humbled and blessed by the genuinely good people I’ve met so far on my journey. I think of Ryan “Guthook” Linn, Zachary “Badger” Davis, and David “Awol” Miller. That’s not to mention those I’ve met on my prep hikes in Wisconsin and Georgia and those I’ve just recently met on this blog and my trail journal. This truly is special community.

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Comments 11

  • George Turner : Jan 14th

    Helpful information. I had already bought the AP and downloaded the AT. Excited to notice that you can get several other trails too.

    • Adrian Casamonte : Jun 8th

      Thanks for the article! To me Strava is the best!! i hope there released a version for hikers too… I love the social component of it 🙂 I use it now n my AGM X1 … cool rugged cheap phone: check it out!! It has (Octa-Core 1.5 GHz, 4GB ram, 64GB mem :O ) ; i got it as a gift and cant leave it alone , didnt knew a phone could endurance taht much… and is really cool since in my hikes i tend to kiss the floor quite usually xP

  • Bob Dexter : Jan 15th

    We’ve used guthook on long section hikes. It’s great for the trail but doesn’t compare with the guide book for towns and near by attractions. As for the guidebook weight. The farther you go the lighter it gets…. You don’t need the information behind you. Besides the guide book is available in an electronic version for the real techies.

  • Caboose' : Jan 19th

    I used the app along with AWOLs map on my 2015 thru hike and found both beneficial and would use them again. With these tools and the 200,000 white blazes I still made 32 wrong turns!

    • Adrian Casamonte : Jun 8th

      I love hking in the rain … so strongly prefer a waterproff rugged phone ! … I discover the agm x1 time ago and still loving it. That line is quite good and not so expensive :S … oh … dang it! now i want to TAKE MY MUSIC AND DO A GOOOD HIKE XP !

  • George Phoenix : Oct 12th

    I don’t see the software version mentioned in your review. Do you recall what it was?

    • Adrian Casamonte : Jun 8th

      Great article ! You know that when going to hike for a long time the charging is usually what comes first to mind … my other concern used to be durability; Which was solved when I bought the x1 (I leave a review: … in general camping is a lot of foresight, foresight and foresight! : D Btw: now the agm x1 has a gold edition and i hope can get one soon 🙂

  • BobG : Aug 23rd

    Does this app let the hiker know about towns? i.e., post offices, grocers, outfitters?

  • Jeff Stroh : Apr 22nd

    Does the app update the New Years info?
    I got the New England section last year as we completed an AT section hike last year.
    I am doing a thru hike in 2019.
    If there are changes to the trail in the mean time is the app updated or do I need to purchase it again?

  • Michael : Apr 20th

    One purchased is the app good for life or does it expire after a certain amount of time


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