Mauna Loa Observatory Access Road

Trail in Mauna Loa Forest Reserve


  • Directions

    Geolocation is not allowed
  • Distance

    17.24 miles

Contact Information


CAUTION: Road striping in progress

Motorists should drive with extra caution along the Mauna Loa Observatory Road. Staff, volunteers, and Boy Scouts will be striping the road. This paved road is one-lane with numerous blind turns and is at a high elevation. Herbicide may be used to remove weeds prior to striping.

This paved, winding, rolling, single lane, two wheel drive road proceeds roughly south for about 3 miles, then southeast for 5 miles, then west over nearly barren lava flows, rising steadily to the NOAA Earth System Research Laboratory at the 11,150' elevation on the north slope of Mauna Loa. This observatory has been providing global carbon dioxide (and climate change) data since the 1950s. Clear weather provides a spectacular view of Mauna Kea, Kohala, Haleakalā (Maui), Hualālai, and the Pōhakuloa saddle. Under optimum conditions, the islands of Kahoʻolawe, Lānaʻi, and Molokaʻi can be seen. The Observatory facilities are not open to the public.

Trails into the Hawaiʻi Volcanoes National Park to the Mauna Loa summit originate at the end of the road.

Allowed Activities
Road Biking
Rules & Regulation
Stay On Trail
Allowed Access

Additional Information


  • No Littering
  • No Plant Sand Dirt Rock Removal
  • No Rock Climbing
  • No Skateboards

Mountain Bikers

Always yield to hikers. Be cautious on blind turns. This road is not an easy mountain bike trail due to the extreme elevation.

Simple Trail Tips

  1. Stay on the trail 
  2. Check the weather 
  3. Watch the time 
  4. Avoid undue risk 
  5. Read all posted signs 
  6. Respect other trail users 
  7. Pack out at least what you pack in

Special Conditions

Do not use any trail or access road that is not delineated by name and color and that may also be displayed on these maps. The marked features are managed for public recreational use. Other trails or roads that branch off from the public features may be on private property, and are not managed for any public recreational use. Access is subject to adjacent landowner approval, and if used without authorization, you will be trespassing and possibly putting yourself at risk. Downloadable resources are provided below.


  • Bicycle
  • 4-wheel drive
  • Pedestrian
  • Sightseeing
  • Tours


  • Parking


  • Nature Study
  • Open Views
  • Scenic Viewpoint
  • Sensitive Area


  • Blind Corner
  • High Elevation
  • Sun Exposure
  • Vehicle Traffic


This road begins at the 27.7 mile point of Daniel K. Inouye Highway (Hwy 200), just Hilo side of Puʻu Huluhulu Native Tree Sanctuary.