Directions to trailhead: From Honolulu, drive west on H-1. Stay on the Moanalua freeway and proceed over Red Hill until you reach the Aiea-Stadium exit. Exit the freeway onto Moanalua Road and proceed through Aiea Town until you hit Aiea Heights Road. Turn right onto Aiea Heights Road and drive up the mountain until you reach Keaiwa Heiau State Recreation Area. Drive past the heiau to the highest part of the park where the camping area is located. Park your car there.
Hike directions: Proceed on foot to the start of the Aiea Loop Trail in the back of the upper parking lot. Hike on the trail for approximately 1.5 miles. At a graded contour section where the trail begins to curve right, you will arrive at a conspicuous junction. Turn left at the junction and proceed no more than 25 paces to a lookout point which overlooks the H-3 freeway. Within 10 paces to the left of the lookout, you will see a fork in the trail. Do not take the left fork that leads straight up the ridge–it leads to Kalauao Valley. Instead take the right fork that contours along the ridge–it leads to the Ko’olau summit.
Hike description: The trail quickly gains the ridgeline and begins as a gentle “rollercoaster”. As you proceed up and down the ridgeline, you will encounter a number of large stately koa trees some of which are incredibly gnarled, crooked, and bent. The humps along the trail become higher and steeper until you reach a fairly level area with many beautiful ohia lehua trees which when covered in red blossoms are a sight to see.
From here the trail switches over to a neighboring ridge by contouring along a section draped in pala’a ferns. After slowly regaining the ridge, the rollercoaster action of the trail resumes until you reach the top of a grassy hilltop which serves as a helicopter landing area.
As you proceed upwards from the helicopter landing area, the character of the ridge changes dramatically–the vegetation is windblown, stunted, and remains close to the ground. During the summer months you may encounter red ohelu berries which provide a tasty little snack. From here, the trail ascends to the summit across several narrow sections with dangerous drop-offs on either side.
The top of Aiea Ridge sits right above the Valley of the Temples. It provides a perfect vantage point to see the jagged cliffs of Kanehoalani forming the northern boundary of Kaneohe Bay, the charming little offshore island of Mokoli’i (Chinaman’s Hat), and sand bars and coral reefs within Kaneohe Bay. And on a clear day you can see the eastern horizon the islands of Moloka’i and Maui.