Mauna Loa hike – going up

Mauna Loa Saddle
Pu’us on the west side of the saddle between Mauna Loa and Mauna Kea, with the Kohala Mountains peeking above the clouds in the background.
Mauna Loa Notice
The trail notice below the observatory.
Mauna Loa Trailhead
The trailhead, a case of spot the cairns.
Mauna Loa 1st Road
The trail, marked by the cairn, crosses the road. The rocks in the foreground are the road!

There are two hiking routes up Mauna Loa. One is the Mauna Loa Trail starting out from Hawaii Volcanoes National Park. This is a 40 miles or so round trip, a multi-day hike requiring a permit. See for information. The other trail is the Observatory Trail, which is reached from Saddle Road. This is the trail I took.

The trail begins at the Mauna Loa Observatory, which monitors atmospheric change. The road up to the observatory begins a hundred yards or so Hilo side of the Mauna Kea Road – Pu’u Huluhulu Native Tree Sanctuary junction. It’s about 17.5 miles and, contrary to some reports, is currently in excellent condition having obviously been repaved in the none too distant past. It’s still single-lane and goes up and down and around many bends, so drive carefully.

Mauna Loa Tube Remnant
This remnant of a lava tube gives some idea of how thin the top can be.

I intended this to be a day trip, which requires an early start. There are two ways to do this. One is to drive up in the evening, sleep in the parking area overnight (all the while acclimating to the altitude), and head out early. The other, which I chose, is to drive up to the observatory early in the morning, spend an hour or so acclimating, and then head out. I left home at 5 a.m. and arrived at the parking area at 7 a.m.. En route I nearly ran over a sheep wandering in the road in the dark and, at the junction, got to see an orange sunrise being welcomed by white-robed followers of what I assumed was some sun-worshipping group.

The trail starts at about 11,000 feet and goes up some 2,700 feet to the summit. It’s a high altitude trail prone to sudden weather changes so the usual cautions apply. There’s a sign at the trailhead that outlines why this hike could be your last. I joke, but the concerns are real. I’d picked a day of fine, settled weather, but packed food, water and clothing for an unscheduled overnight stop.

That said, I headed out on the very rough dirt road that is the start of the trail. This is a road for 4-wheel drive trucks with strong motors and lifted suspensions that make the truck bed seem detached from the wheels. I’ve hiked at altitude a moderate amount and not had any problems, but I know to take my time and be alert to signs of altitude sickness.

After about half a mile the trail proper takes off to the left. There’s a nice, clear sign marking the spot. The trail itself is less obvious. Most of this trail is marked by cairns. Sometimes there’s a splash of white or yellow paint, sometimes a stick or pole, but the cairns are the main guide. The only thing is, the cairns aren’t always obvious as the trailhead photo shows. It’s a good idea to identify the next cairn before leaving the one you’re at.

A lot of this trail passes over rounded pahoehoe lava. I prefer hiking on this to sharp a’a lava. At least with pahoehoe I have a solid surface to place my foot and to push off from. That said, there are times when the surface crackles and I’m keenly aware the area is riddled with lava tubes, some topped with a thin crust that could easily give way. That’s one reason why I try not to stray from the trail.

When I hike, I often have songs running through my head and, on hikes like this, I inevitably end up humming “Put one foot in front of the other” from the 1970 movie Santa Claus is Comin’ to Town (don’t ask). It is, however, a one-foot-in-front-of-the-other kind of hike, a steady climb at a steady pace, watching ones steps.

About 45 minutes in, I crossed the dirt road I’d started on (which zigzags up the mountains most of the way to the summit). I’d walked up the road once before looking for this crossing and hadn’t identified it. Now I recognized that I’d walked past it. A lot of the trail is like this – a mishmash of lava and ups and downs, with a distinctive feature here and there. There’s a broken lava tube marked by two big cairns and another junction with the road. The trail follows the road at this point until it comes to a gate marking the national park boundary. Then it veers off, up the hill, to the right on an easily followed cinder section, crosses the road a third time, and finally winds up another half mile to the edge of North Pit, the northern most feature of Moku’āweoweo, the summit caldera.

Dare I say that this view isn’t the most spectacular? The floor of North Pit is only about 10 feet below the rim and, since it stretches out a good way ahead, that’s really most of what there is to see at this point. It’s still an impressive view. The trail to Mauna Loa cabin angles across the North Pit floor and in the distance are the higher cliffs of the main crater. Best of all, I was feeling pretty good, it was only 11:00 a.m. (three and a quarter hours to this point), and the weather continued to be and look great.

Tomorrow, I’ll post my hike from North Pit up the Summit Trail.

For more information about the Mauna Loa Observatory Trail, go to or (under Things To Do, check Scenic Drives for the road up to the observatory and Hikes & Trails for the trail).

Mauna Loa Gate
The road ends at a locked gate. The trail takes off up to the right.

2 thoughts on “Mauna Loa hike – going up

  1. Jennifer Liepin

    Mauna Loa Summit Day Hike was quite an accomplishment to climb, but I am unsure if I would ever do it again or recommend it to most people. It is demanding enough that if someone is not well prepared – in terms of fitness or ability to acclimate to the altitude – it would be quite dangerous to hike.

    However, I’m glad to be joining you in having hiked and taken in all the beauty of the largest volcano on the world.

    I wrote about my own experience completing the 14 mile RT hike (supposed to be 13, but we got a bit lost on the way down…)


    1. Graham Post author

      Yes, it’s quite the hike. I’m thinking of doing it again, but getting a pre-dawn start, probably when the moon is full. I agree, it’s not a hike I’d necessarily recommend because of the dangers. Altitude sickness isn’t to be messed with. When I felt a bit of it I turned around and headed down. I think acclimating for an hour or so at the parking area is very important.

      I hope you enjoyed visit to the Big Island. I’ll hop over and take a look at your post.


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