Manukā State Wayside Park and Natural Area Reserve occupy more than 25,000 acres on both sides of Highway 11 west of Naʻālehu in the Kaʻū District. Manukā means blundering in the Hawaiian language, and is also the name of an ancient land subdivision that extended from the ocean to the upland forest, known as an ahupua'a. The eight acre arboretum near the highway was cleared and replanted from the 1930s to 1950s with 48 species of native plants and more than 130 species of other tropical plants. Manukā was added to the Territorial Park System in 1952 before Hawai'i was a state. There is a two mile trail called the Nature Trail that traverses the arboretum and passes a forested pit crater and several eroded archaeological sites in an ancient agricultural area. The trailhead is also a highway rest stop with trash, restrooms, and a picnic area. There is no water available. Open shelter campsites are available on a first-come, first-served basis. The Nature Trail is for foot traffic only. All motorized vehicles and mountain bikes are prohibited. 

Trailhead: On Hwy. 11 about 20 miles west of Naʻālehu, find the signed turn for Manukā State Wayside between the 80 and 81 mile markers (closer to mile marker 81). Drive a short distance into the Park and find the parking lot. The road in and out of the park is very narrow, so slow down getting off the highway when you turn into the Park. 

Weather

Gear: Standard hiking gear. The hike ranges from 1800' to 2200' above sea level. Expect mosquitoes and plan for rain. The trail is pretty rough, so sturdy shoes are a good idea. 

Hike: Walk across the parking area and find the beginning of the Nature Trail marked with a brown and yellow sign. Pass a few more signs and a kiosk that may have some trail guides, and find the beginning of the trail as it gradually goes uphill. Hike uphill for 3/4 of a mile and find a short spur trail that leads to an overgrown pit crater. Stay away from the edge. It looks like there are a few lava tube segments along the walls of the crater. After viewing the crater, hike for another half of a mile until you find the trail's highpoint and rest area. Near the highpoint, there are several old walls and other eroded ancient structures that were part of an agricultural complex. Further along the trail as you start downhill, look for large earthen mounds used for some agricultural purpose. The trail continues downhill as it gets more and more full of clinky ʻaʻā lava rocks making for some uncertain footing. Eventually, the trail drops you off behind one of the picnic areas to the west of the parking area.