A strenuous day hike to the top of Hawaii’s highest mountain
NOTICE: CURRENT CLOSURE
As of July 15, 2019, The Mauna Kea Access Road (and concurrent trail) are closed indefinitely to provide construction access for the controversial Thirty Meter Telescope. This closure includes the Visitor Information Station and its trailhead.
The best way to look for updates on this is to periodically check the official website for the visitor station, and search the web about “TMT protests” for more general information about what’s going on.
Overview
By some measures, Hawaii’s Mauna Kea is considered to be the tallest mountain in the world. This is because its height, as measured from the bottom of the ocean floor, is even greater than Mount Everest.
Mauna Loa may be the “largest” volcano in all of Hawaii (And the world, for that matter), but Mauna Kea is the highest. At 13,796 feet, it’s a mere 196 feet higher than Mauna Loa.
Mauna Kea is classified as dormant, while Mauna Loa is still active.
Mauna Kea is not only popular for its height – it’s primarily known because of its accessibility. There’s a mostly-paved road that goes to the top, so it’s a neat fact that you can drive from sea level to the summit in only a few hours (Hello, altitude sickness!).
The volcano is topped by a world class, Martian-looking weather observatory, lofty among Hawaii’s dark skies of the Pacific Ocean. A quick Google search tells me that it’s the “world’s largest observatory for optical, infrared, and sub-millimeter astronomy.”
Adjacent to the road, there’s a 6-mile hiking trail to the summit. Fortunately much of the trail is out of sight of the road. The path is usually referred to as the Mauna Kea Trail, but sometimes it’s called the Humu’Ula Trail.
Humu’Ula Trail Guide (Mauna Kea Trail)
PERMITS: Permits are not required, though it’s strongly recommended to check in at the Mauna Kea Visitor Information Station immediatley before and after your hike.
DESIGNATION: Mauna Kea Ice Age Natural Area Reserve – Hawaii State Department of Land and Natural Resources – managed by the University of Hawaii
BEST SEASONS: year-round, though the highest potential for snow is in winter and spring
DISTANCE: 12 miles round-trip
WATER: none, carry plenty
ELEVATION: trailhead 9,200ft – summit 13,796ft – gain 4,600ft
ACCESS: paved roads to trailhead
DRIVING: From the town of Hilo, drive west approximately 22 miles on Route 200 (Saddle Road). Turn right on the Mauna Kea Access Road – it will be after mile marker 27, and before mile marker 28. Drive 6 miles up the road to the Visitor Information Station.
From Kona, it’s a driving distance of little over 50 miles via Highway 190 and 200.
Mauna Kea Access Road on Google Maps will point you in the right direction.
GUIDEBOOK: Hawaii The Big Island Revealed
WARNING: Hiking on Mauna Kea is a strenuous trek to the summit of a serious mountain. Despite the tropical locale, snowy conditions and hypothermia are always possible. Stay hydrated and be conscious of your vulnerability to altitude sickness, or acute mountain sickness. Be prepared!
Mauna Kea Map
Here’s a map that shows the Humuula Trail up Mauna Kea Mountain, in addition to several other features. This map is a handout as received from the Information Station in 2014.

About Mauna Kea Mountain
With a summit measured at 13,796 feet above sea level, Mauna Kea is the highest mountain in Hawaii. Its prominence from the from the bottom of the Pacific Ocean is over 33,000ft, by most accounts rendering it as the tallest mountain in the world.
When measured versus Mount Everest, Mauna Kea is technically a “taller” mountain. Mount Everest has a much higher elevation, making Everest the overall highest mountain in the world.
In other words, you can think of Mount Everest as a shorter person standing on a stool, and Mauna Kea as a taller person standing in ditch.
Summit Observatories and Telescopes
Mauna Kea is one of the best sites in the world for astronomical observation. This is due to a combination of dark skies, arid air, clear weather, low air pollution, and low atmospheric turbulence.
The summit road was built in 1968 and the first telescope followed in 1970. Some of the more famous observatories located here are Japan’s Subaru Telescope, the twin Keck Telescopes (reportedly the word’s most productive optical and infrared scopes), and NASA’s infrared facility.
Keck and Subaru have visitor centers, but these observatories are otherwise closed to public use. The Information Station (down the mountain) usually holds a nightly star party.
Since its legislative approval in 2013, the planned Thirty Meter Telescope (TMT) has been the subject of ongoing protests and news headlines, as Native Hawaiians rally in opposition to its construction.

Native Reverance
The name Mauna Kea translates literally as “White Mountain,” presumably because of its snow-capped nature in winter. However, some sources claim the name is rooted from the phrase Mauna Wakea – Wakea is the name of the Hawaiian sky god. It’s said in their mythology that Wakea and Papa (goddess of the earth) were married and the Hawaiian islands are their children, with Mauna Kea as first born.
Hawaiians consider all of the island peaks to be sacred, but Mauna Kea gains special significance as the highest mountain and therefore the most sacred of all. They say only the gods dwell on the summits.
Hikers are asked not to stand on the true summit, as this action is viewed as blatantly disrespectful to native Hawaiians and their culture.
The mountain is home to a wide array of archaeological sites, including quarries and burial grounds. For more on this, check out this detailed survey conducted in 2013.
Geology
Mauna Kea is a classified as a dormant volcano, thought to have erupted as recently as 4,000 years ago. It once went through a shield stage, as is seen now in the more gentle slopes on the active Mauna Loa.
Mauna Kea is older than its neighbor (and thought to be about one million years old), so it has had more time to erode into a more prominent profile. Also, as opposed to Mauna Loa, it does not have a singular summit caldera. Alternatively it has several cinder and pumice cones near the top, but this does not necessarily mean that it never had a main crater.
Lake Waiau
Lake Waiau is a main feature seen along the trail, technically reached via a short spur trail. Appearing as a non-descript puddle in the above photo, you’re actually looking at the only alpine lake in Hawaii, and the highest lake in the entire Pacific Basin. It’s often more full than what you see here.
Glacial activity played a role in carving the shape of today’s Mauna Kea, resulting in this basin and subsequent lake, fed by snowmelt and permafrost. Lake Waiau is a strange anomoly, as water normally percolates easily into lava rock, but here it does not. It’s thought that this is because of a unique set of volcanic conditions.
It’s also commonly said that in prehistoric times, Hawaiians are thought to have dipped the umbilical cords of their children into the lake to bless them with the strength of the mountain.
Please respect native Hawaiian culture here and do not entire the lake or disturb its shores (Why would you dream of getting into the lake at this elevation anyway?). To this day, Hawaiians will often leave ceremonious shrines and offerings along its banks.
It’s additionally recognized as the 3rd highest lake in the United States.
Mauna Kea Weather
Hikers should be prepared for winter conditions at any time of the year.
This chart provides a great picture of Mauna Kea’s climate, whereas this page gives up to date readings from the summit’s various observatories, including wind speed, temperature (Celcius only), and other scientific readings.
Conditions were favorable on the day I hiked this trail, but my rain shell stayed on to cut the wind and UV rays for nearly the whole day. UV rays are more intense and dehydration occurs more rapidly on the mountain than elsewhere.
Difficulty
Given the high elevation, harsh weather, and strenous nature of ascending (and descending) 4,600ft in a single day, I’d rate this as a very strenuous and serious hike, lessened only by its proximity to a road.
Acclimating to the High Elevation
The most significant barrier to visitors wanting to hike Mauna Kea is its high elevation. A day hike that begins at 9,200ft and tops out at 13,800ft is no joke! Add this to the fact that most of us visiting Hawaii won’t have any acclimitization to this kind of elevation, and you have a problem.
Personally I solved this by completing a four-day backpack up the neighboring Mauna Loa in Hawaii Volcanoes National Park. This ended up being the perfect way to train and acclimate (at the same time!) for this day hike up Mauna Kea.
Another way to acclimate prior to the hike is spend some time at the nearby Mauna Kea Recreation Area, where there are cabins available for rent. Its elevation of 6,500 isn’t super-high, but it sure beats sea level.
Camping
No camping is allowed along the Humu’Ula Trail, so backpacking is not an option.
The Observatory Road
The paved Observatory Road that leads to the Visitor Information Station continues up the mountain as a dirt track, which is paved once again at the mountain’s summit.
The Mauna Kea Trail roughly parallels the road and rejoins it at the top of the mountain, so it’s possible to do this as a one-way hike via a friend with a 4wd vehicle, or through hitchhiking. I haven’t driven the road, but it’s reportedly okay for passenger vehicles with care in good conditions.
Trail Description
From the Ellison Onizuka Visitor Center (Information Station), cross the paved road and walk a 4wd road for a quarter mile, where you’ll see the trail leave the road on the right.
The Mauna Kea (Humu’Ula) Trail is marked regularly with iron poles. This makes it simple to follow, even in areas where the terrain underfoot doesn’t clearly reveal the path.
In about a half mile you reach the boundary of the state reserve area.
The early stretch of the trail feature its steepest climbing, averaging about 1,000ft of gain for per mile.
The incline will let up only slightly as you climb an additional thousand feet to above 13,000ft above sea level (whew!), and reach the junction with Lake Waiau. The lake is often advertised as a main attraction of the hike, but native Hawaiians ask that you generally leave it alone, not even as a drinking water source unless you’re in dire need.
A clear spur trail leads from the lake intersection to the road, if you want to bail out.
Continuing up the Mauna Kea Humu’Ula Trail, you’ll reach the paved road. Here you’ll leave the footpath and walk the road for about a mile. A sign with a hiker insignia marks the final stretch of trail that leaves the road to the right for the summit, but standing on this sacred site is discouraged.
My Trip Notes and Photos
The trail starts at the Visitor Information Station (Onizuka Visitor Center) at a mere 9,200 feet… so the trail gains about 4,600 feet, which is actually slightly higher than hiking out from the bottom of the Grand Canyon… not to mention the thin air up there. Sounds fun!
And it was a fun hike, despite its difficulty and proximity to the road. The road doesn’t like to play nice with rental cars anyway, especially when the drivers haven’t discovered 1st or 2nd gear in their auto transmissions. Smoke rises from this dormant volcano as a parade of brake pads burns into dust.
We stayed at the Wild Ginger Hostel in Hilo as base camp for this day hike. Some nearby rustic, expensive cabins (Mauna Kea Recreation Area) turned up in our pre-trip research, but they were pricy and didn’t even have water in 2014, so we opted to do a few extra hours of driving in order to have the luxuries of town.
The Visitor Center asks for you to sign their register book before you embark on the day hike, and it’s a good idea to do this. It’s easy to get sick or into trouble when you go directly from the beach to 13,000 feet.
We did this hike in late January 2014, and there was a significant snowstorm on the very next day! It can snow up here at any time of year, and all of the usual precautions involved in hiking up 14,000-foot-mountains apply here, too.
It was really, really windy.
Approaching the science-fiction-space-station summit – Isaac Asimov should have been buried here, or maybe Carl Sagan, or maybe Matt McConaughey’s character from the movie Contact.
Yep, that’s the ocean out there, as viewed from the final summit spur trail.

returning down the mountain
Mauna Loa, the “long mountain,” dominates the view to the south.
There was a lot of activity back at the Visitor Center in preparation of the nightly “star party,” an event where star-geeks roll out some very huge, very expensive telescopes to show you a lot of very cool stuff, like the rings of Saturn and a lot of very, very, very old light from distant galaxies. If you ask nicely they might re-enact scenes from Star Wars with their laser pointers.
It may not sound like it, but Star Parties are actually really awesome. They only hold one once a year at the South Rim of the Grand Canyon (In June), and it’s kind of a big deal. Mauna Kea gets to have a Star Party every night.
We drove back to Hilo and had a delicious, somewhat fancy dinner at Cafe Pesto.
For more information, check out this book. I think it’s the best guidebook available for anyone visiting the Big Island of Hawaii (Backpackers, beach-goers, etc. you name it).
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