Garmin GPSMAP 66sr Review & Test

The Garmin GPSMAP 66sr is the best handheld GPS out there. There, I said it. I spent several weeks using the GPSMAP 66sr on the hiking trails, and in this review, I'll tell you what my experience has been. I've even tested the 66sr within the walls of the Grand Canyon, and I'll share my results in this review.

In this Guide:

GNSS / Multi-Band Performance
Grand Canyon Test Results
Battery Life, Mapping, and Other Notable Features
Which GPSMAP Model Should You Get?

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Garmin GPSMAP 66sr GPS Performance

Gpsmap 66sr Accuracy — I can consistently get a 6ft accuracy reading on the GPSMAP 66r, which always beats my GPSMAP 66i, usually getting between 9-12ft of accuracy.

Since the positioning on the 66sr is likely the main draw, let's jump right into it. Overall the positioning accuracy and reliability was the highlight of this device. The 66sr can get a position very quickly and often with a 6ft (1.8m) level of accuracy. If you consider that most trails are about 4 ft wide, and a human with their arms outstretched is generally around 6ft wide, this should be more than enough for navigating the backcountry. Although there are always variables when using a GPS unit, overall, the tracks you record on the 66sr should be the most accurate.

If you're not familiar with how GPS works from a technical perspective, I highly recommend checking out my article explaining the concepts here. It will help you understand how to get the most out of your GPS.

Multi-GNSS Functionality

The 66sr is a multi-GNSS receiver, and it can pick up signals from multiple satellite systems: GPS (USA), GLONASS (Russia), GALILEO (Europe) QZSS (Japan), and IRSS (India). The practical application of this is to have more satellites in the sky to choose from, making a fix quicker and allowing the chipset to select the best quality signals.

The only (public) satellite constellation that is missing is BeiDou (China). You can find BeiDou support on many smartphones, but not on Garmin GPS units (yet). It's not a big deal; the GNSS systems that the 66sr supports allow it to choose from over 100 satellites orbiting the earth.

Gpsmap 66sr Spaced Satellites — Having satellite fixes farther apart (in the outer circle) like 33 and 27 here will give you a better fix than having them all in the middle (closer to directly overhead). The ability to use satellites from multiple GNSS systems allows the 66sr to pick and choose the best signals and determine your location.

Gpsmap 66sr Gnss Settings — You can choose from GPS only, or all of the GNSS systems. You can't individually pick which GNSS systems to use. Switching to "GPS only" gives me a usual accuracy of 10ft, which is respectable.

Multi-Band Functionality

Gpsmap 66sr Galileo Bands — Garmin multi-band receivers like the 66sr display the satellites they have fixes for and their bands (like the E1 and E5a bands for Galileo here). Each GNSS has its band naming convention, but multi-band receiving is the same principle for each GNSS, even if some specifics are different.

The 66sr is multi-band. Think of bands on GPS like the radio station bands of AM and FM. The original GPS satellites broadcast on the L1 band, and you can think of it like AM radio. You can listen to it, but if there's interference, it doesn't sound great. The L1 band is the most prone to interference, which leads to incomplete positioning data received, and therefore a less accurate position fix.

Since the original GPS satellites went up in 1993, many new and improved satellites have been launched. New signal bands have been a part of the technological advances on these satellites. One of these new bands is the L5 band, first launched in 2010. If the old L1 band is AM radio, think of L5 as FM radio. The signal quality is better, and the data received is generally of better quality.

And the GNSS satellites broadcast on both the L1 and L5 bands at the same time. When the 66sr receives multi-band from a satellite, it can use those multiple signals to do quality analysis and correction, reducing the error introduced by bouncing signals (multi-path error) and the earth's atmosphere.

Gpsmap 66sr Multi Band Settings — You can disable multi-band reception. When I do this I generally get a best accuracy of 10 feet.

Accuracy and Consistency

Getting a fix to within 6 feet when standing still is just half of the equation. You want a GPS unit to consistently have that level of accuracy as you move through tree cover, canyons, valleys, etc. After using the 66sr in a wide variety of terrain, including heavy PNW canopy and deep canyons, I can say that the many satellite and band options available to the 66sr have meant that I consistently get a good (often 6ft) level of accuracy, regardless of the terrain.

I would highly recommend getting this if your outdoor activity involves dense foliage, metropolitan areas with tall skylines, or deep canyons. This GPS will give you better accuracy than any other handheld outdoor GPS currently on the market REI Reviewer

GPS Altitude

Gpsmap 66sr Elevation — The USGS disc in the back is officially listed at 25.19 feet above sea level. The GPS elevation is only about 4 feet off, and the barometric altimeter is only 2 feet off. That's about as good as I've seen from a handheld GPS.

I've never relied on elevation readings on handheld or watch GPS units. In the past, they've been up to hundreds of feet off the mark. But the multi-band and multi-GNSS systems on the 66sr have been usually within 10 feet of known elevations. I set the altimeter auto-calibration to once when the weather is stable and continuous if the weather is changing. The auto-calibration uses a combination of GPS and DEM map info (Digital Elevation Model) to guess your current elevation and calibrate from that. Given that the 66sr positioning is more precise, it probably positively affects the barometric altimeter calibration.

GPS Test

For this GPS test I was lucky enough to be able to bring the 66sr to the Grand Canyon for a Rim 2 Rim 2 Rim hike. I compared it to recordings made on the GPSMAP 66i (GPS + Galileo), Fenix 6x Pro Solar (GPS + Galileo), and Gaia GPS on an iPhone 12 Pro Max (GPS, GLONASS, Galileo, QZSS and BeiDou).

Gpsmap 66sr Gps Test 2 — There were some sections along steep walls where all the units struggled and the 66sr (green) was about 25 feet off.

Gpsmap 66sr Gps Test 3 — Generally within tougher canyons, the 66sr (green) was solid while the others struggled.

Gpsmap 66sr Gps Test 4 — Several sections where the 66i, Fenix 6x, and iPhone all lost their minds and went crazy. The 66sr never had a freak-out like this on its own.

Gpsmap 66sr Gps Test 5 — But there was the occasional challenging spot where all the units struggled.

Overall I don't expect any GPS to give me a super-accurate track when traversing the Grand Canyon, but the 66sr came the closest. Whenever there is a freakout along a canyon wall and the GPS tracks you as far away and then magically back the next second, it adds distance onto the track.

Official NPS distance - North Kaibab > River Trail > Bright Angel - 22.7 miles + 0.5 farting around = 23.2 miles
GPSMAP 66sr - 24.6 miles - 4,987 ft ascent
GPSMAP 66i - 25.4 miles - 4,993 ft ascent
Fenix 6x Pro Solar - 24.96 miles - 4,831 ft ascent
iPhone 12 Pro Max - 26.7 miles - 5,033 ft ascent

GPS Test 1

GPS Test 2

Other GPS Notes

The GPSMAP 66sr support WAAS/EGNOS, and I'm guessing it's because it doesn't add much to the accuracy it can achieve with multi-GNSS and multi-band.
Disabling multi-GNSS or multi-band didn't have any noticeable effect on prolonging battery life.
Here in the Southern California area, I've noticed that Galileo almost always gets multi-band from all the satellites, whereas GLONASS and GPS only have multi-band from a few satellites.
You can also save your track to a RINEX file on the 66sr.
Make sure you sync your GPSMAP 66sr with Garmin Connect before heading out, which will preload satellite information onto the device in the form of an EPO file. The EPO file has orbit information for all the GNSS satellites, compiled from the internet. This saves the 66sr some work in decoding and processing that information directly from the GNSS signal.

GPSMAP 66sr Battery Life

Gpsmap 66sr Charging — The 66sr charges with a micro-USB cable, which is supplied (but without a wall plug). The charging screen here is the only place (without a third-party app) that you can view the actual charge percentage.

First off, unlike the GPSMAP 65s, the lithium-ion battery on the 66sr is internal, and you can't swap it out or use AAs. I know that for some, this is a deal-breaker. But in a world where you probably carry other devices (like a smartphone) with internal batteries, I think it's fine. In fact, for me, carrying a smartphone, 66sr, and headlamp, all of which have internal batteries, I end up just carrying one inexpensive USB charger and it takes care of them all. So in that respect, I find the internal battery easier than having to carry extra AA batteries.

Gpsmap 66sr Battery0 Widget — Unfortunately there is no built-in battery percentage display, you only get a small graphical battery icon which isn't too helpful. The good news is that you can install third-party apps from the Connect IQ store for free, including this invaluable (and free) battery widget. Once installed, hit the power button to access the status screen, then arrow right or left to access this widget.

Overall the 66sr battery will be great for most hikers and backpackers. Garmin reports that you can get 36 hours of run time in GPS mode, and that was just a few hours more than I was getting in real-world usage. Generally when hiking, checking the device and dropping waypoints about 3-4 times an hour, I was getting around 32 hours of battery life. This was with the backlight at 100% and battery save mode on with a 15 second timeout. Tweaking other settings only had a minimal effect on battery life. If you notched the backlight down you can probably squeeze another hour or two out of the battery.

Gpsmap 66sr Battery Saver — I think the best feature you have to save your battery is the appropriately named "battery saver" setting. When it's on, the screen (a major culprit of battery drain) will shut off when the backlight times out. To wake the screen, simply tap the power key again.

Similar to other Garmin GPS devices, there is an "Expedition Mode" where the screen turns off, the device goes into low power mode, and only occasional GPS track points are recorded (about once an hour). I've found the tracking interval not to be very helpful as a hiker, so I don't use it. But if Expedition Mode fits into your workflow, you can allegedly get 450 hours of battery life using it.

Maps on the 66sr

Gpsmap 66sr Map Detail — I've found that the trail coverage and detail level of the preloaded maps is great, at least for my hikes in the western USA. For example, in this shot, you can see that smaller spur and use trails are included and labeled.

The GPSMAP 66sr comes pre-loaded with Garmin TopoActive maps, and they work well for the outdoors. A few years ago TopoActive maps didn't include many trails, but today they are based on Open Street Maps (OSM) and I've found that the Garmin cartography team does a respectable job of including documented trails in the map set. The maps are updated fairly often and include a list of POIs to search for (like hospitals, etc.).

Gpsmap 66sr Routing — Navigation is the standard Garmin experience. Routes will give you prompted guidance as you approach a turn. When navigating by track, you simply stay on the purple line.

The TopoActive maps are routable, meaning that you can search for a destination and the 66sr will give you turn by turn instructions on how to get there. It's a good feature to have, but if you want to plan a hike, I'd do so with tools beforehand to ensure that you're on a hiking trail and not a less attractive option like a fire road.

And like other Garmin outdoors units with maps, you can't search for a street address unless you install the optional CityNavigator maps, an additional purchase. If you know the ballpark of where you want to go, an easy workaround is to move the map cursor over the spot and hit "GO" from there.

If you want a more detailed map, you can purchase Garmin's Topo 24k maps and load them on the device, or just load free OSM maps on there, which I recommend. The 16gb internal memory has about 5gb of space left for extra maps, and you can pop up to a 32GB Class 10 MicroSD card in there for more capacity. If you will save a lot of data on the device, make sure you check out the (not too shabby) data limitations for the 66sr.

Gpsmap 66sr Map Public Land — There is a map layer for public land boundaries that you can toggle on or off (as you can for all map layers). I've found that only federal and some state boundaries were shown. Many local and county parks didn't show as public lands.

Gpsmap 66s Sr Birdseye — The Garmin Birdseye imagery is decent. Overall it's much better than it was initially, but not the best you can get out there. On the left is the maximum zoom on Birdseye and on the right is the maximum zoom on Google Maps. Maybe it's too much to ask that Garmin compete with Google on this front. And just a note, you can't (easily) download Google satellite photos to the unit (or any unit aside from an Android phone).

Gpsmap 66sr Birdseye On Unit — Here's what the same area looks like on the 66sr screen. On the smaller screen, the resolution is more acceptable. Note that you can turn the Birdseye layer on and off if you'd like to see the regular vector map.

Gpsmap 66sr Connected To Laptop — Connecting the 66sr to your computer allows you to access the TopoActive and Birdseye maps in the free Garmin Basecamp program. Garmin Basecamp is an excellent tool for planning an outdoor adventure and then transferring the data (waypoints, tracks, etc.) to the 66sr.

Notable Features on the 66sr

Gpsmap 66sr Rugged Design — The GPSMAP 66sr is a purpose-built outdoors GPS unit. Any openings, such as the Micro-USB port or microSD card slot are protected with a rubberized cap. The entire unit is also surrounded by a rubberized band, making it easy to hold on to in all conditions.

First off, you might be asking yourself why get a dedicated GPS unit when you can just use your phone, and it's a good question, especially as phones get more durable. For me, the answer is easy. A dedicated GPS like the 66sr is built for the outdoors, and that includes rain. I never have a problem using a device like the 66sr with one hand, regardless of the conditions, unlike a touch screen. I also know that I can drop it, sit on it, whatever, and it still works.

Gpsmap 66sr Brightness — When I was researching this guide, I saw some reports of the 66sr screen being much brighter than the other 66 models. Here's a 66i on the left and a 66sr on the right, both at 100% backlight. In the 66sr that I have, I haven't noticed any difference in the screen brightness.

Gpsmap 66sr Button Tones — A great feature on devices like the 66sr is the audio and haptic feedback when clicking a button. You always get a "click" when pressing a button, so you know if it's been clicked or not. And you can also adjust the volume level of a tone, or just turn it off.

Gpsmap 66sr Profiles — Like the other 66 models, the 66sr has profiles, which let you customize the data and menu items for different activities and easily switch between them.

Gpsmap 66sr Custom Screen — As with most all Garmin units, the device is customizable. I can set up the main menu icons based on how I use the device and remove features that I don't care about. I can also pick the data fields that I want to display.

Gpsmap Connect Iq — You can download third-party apps from the Connect IQ store and install them on the device.

Gpsmap 66sr Apps — The 66sr syncs wirelessly with Garmin Explore (the outdoors navigation portal and app on the left) and Garmin Connect (the fitness portal and app on the right). It can also upload and sync with its internal WiFi. And you can use it with Garmin Basecamp, which continues to be a great tool. If you're a computer geek, you can attach the 66sr as a hard drive and pull off your GPX files directly.

Like many other Garmin handhelds, the 66sr has barometric altitude, barometer, and a magnetic compass. The altimeter is listed as +/- 50 to 125 feet, but I've found that I can usually get to within 10 feet of a known altitude, which is good in my book.

Gpsmap 66sr Weather — You will need a connection to the outside world via WiFi or Bluetooth phone to get weather information, making it only useful before you hit the trail if you're out of phone range. It's not like the GPSMAP 66i where you can request a weather report via satellite.

Gpsmap 66sr Interface — If you've never used a Garmin before and are coming from a smartphone, the Garmin interface will feel like a step back to 1995. It's not the slickest, but at this point works well. And the simplicity can be an advantage when conditions are challenging.

Should You Get the GPSMAP 66sr?

Gpsmap 66sr And 66i — For me, there are only two contenders when it comes to a handheld GPS, the 66sr (left) and the 66i (right). If you need InReach, the 66i is the move (which I often use to document my guides). If I didn't need InReach, I'd get the 66sr in a second.

Everyone is different, and the alphabet soup of Garmin model numbers can be confusing, but here's what I would recommend for most outdoors folks.

If you need the best accuracy available in a consumer handheld GPS, then get the GPSMAP 66sr. It's great for geocaching, hunting, and documenting land features.
If you want that same level of accuracy with AA batteries at a lower price, get a GPSMAP 65s.
If you want acceptable GPS performance combined with InReach communications, get a GPSMAP 66i,
If you want to the best of both worlds, get a GPSMAP 66sr and a separate InReach Mini.
If you don't care about GPS accuracy or outdoor durability, and just want something to navigate with in fair weather, try a smartphone with Gaia GPS.
If you are considering a GPSMAP 66s (no maps, no multi-band) or a GPSMAP 66st (no multi-band), I'd say you be much better off spending the incremental extra cost and getting the GPSMAP 66sr.

Tips for Using the GPSMAP 66sr

GPSMAP 66sr Resources

GPSMAP 66sr Unboxing

Gpsmap 66sr Unboxing 1

Gpsmap 66sr Unboxing 2

Gpsmap 66sr Unboxing 3

Basic GPS Concepts in Use

Copying Device Maps to Computer

Need More Info?

Have a question about the guide or want to see what other people are saying/asking? View the Youtube comments for this video. Leave a comment and I will do my best to respond.

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This Guide Was Written by Cris Hazzard

Cris Hazzard 4 Mile Trail Yosemite
Hi, I'm Cris Hazzard, aka Hiking Guy, a professional outdoors guide, hiking expert, and author based in Southern California. I created this website to share all the great hikes I do with everyone else out there. This site is different because it gives detailed directions that even the beginning hiker can follow. I also share what hiking gear works and doesn't so you don't waste money. I don't do sponsored or promoted content; I share only the gear recommendations, hikes, and tips that I would with my family and friends. If you like the website and YouTube channel, please support these free guides (I couldn't do it without folks like you!). You can stay up to date with my new guides by following me on YouTube, Instagram, or by subscribing to my monthly newsletter.