What to Do in Hawaii: Hike Aiea Loop Bisectional

Literally thousands of folks have completed the 5-mile Aiea Loop Trail on the island of Oahu in Hawaii. I'd wager that very few of these same folks know about a trail that, for the most part, follows a ridge that splits the loop right down the middle.

The name "Aiea Loop Bisectional" was coined by my hiking colleague Wing Ng, who told me about where to look for the route.

How To Get There

If you drive from downtown Honolulu, take the H-1 freeway westbound. Just past the Likelike Highway offramp, H-1 will split. Stay left and continue over Red Hill. Take the exit toward Stadium/Aiea. Merge onto Moanalua Road. Turn right onto Aiea Heights Drive. Just past a 7-11 store, reach a stoplight. Turn left, still on Aiea Heights Drive. Follow Aiea Heights Drive uphill for about 2 miles. It ends at Keaiwa Heiau State Park. Enter the park and follow the road to its highest point. Park near a restroom there.

If traveling by city bus, board the #74 (Aiea Heights). Exit at the last stop at Aiea Heights Drive and Hoapono Place. The walk to the park entrance from there takes less than five minutes.

Hike Description

Assuming a starting point by the upper restroom and parking lot, follow the loop trail for about 20-25 minutes, passing a powerline tower (to the right), the trail leading down to Kalauao Valley (to the left), and a second powerline tower (right). As you move along the trail, particularly on sections where you're contouring along the side of the ridge, look off to the right to see a ridge that heads away and down.

The bisectional trail sits atop that ridge. You'll know you've gone past it if you reach the super muddy sections and the topping-out point of the loop. The bisectional ridge begins perhaps an eighth of a mile before the highest point of the ridge at a fairly level and broad rooty area of the loop trail. A ribbon marked the spot every time I've hiked the route but trail markers sometimes blow away or are removed so take heed.

Once you find the trail, it's a matter of following the ridge for about a mile to its bottoming out point at the usually waterless Aiea Stream. When you reach the stream, be prepared to encounter overgrown conditions. Fear not. If you think you're lost, just continue to work your way downstream until you reach that rocky "bridge" that Aiea Loop hikers should readily recall. From there, follow the loop trail as it climbs through the muddy, rutted slope to where it comes out near the lower camping area.

For more of a workout or for variety, you can hike the bisectional from the bottom up, starting at the river and climbing the ridge to where it intersects the upper part of the loop trail.

As a sidenote, I've learned that the bisectional trail is used by crews hired by the electric company to cut away at trees which begin to crowd powerlines. In fact, on my most recent trek along the trail (late-summer '96), I stumbled upon a trio of tree trimmers napping in a shady spot along the path. By the way they bolted upright on my approach, I could tell I surprised the hell out of them when they saw me, probably because they never expected anyone to be hiking in the area or perhaps because they thought I was a supervisor coming to bust them [g]. Whatever the case, I had a good chuckle at their expense when I was out of their seeing and hearing range.

If you've done the Aiea Loop before and want to try a different twist, try the bisectional route. I think you'll enjoy the variety.