One of seven amphitheater valleys carved from the extinct Kohala Volcano along the northern shore of the Big Island, Waimanu Valley is something of a Holy Grail to Hawaii hikers. Abandoned in the late 1940s, it's one of the few valleys in Hawaii where humans have not altered the watershed, save the ancient Hawaiians who built their rice and taro farms on streambeds and largely let nature do its thing (there is a small state-maintained campground and the remants of buildings but nothing major). Waimanu is raw, untouched Hawaii ats its pristine best. These photos from Flickr give you a taste). Getting to Waimanu, however, is no small feat.

First you tackle a 1,200-foot switchback ascent on the muddy Muliwai trail up a steep cliff wall from neighboring Waipio Valley. Native Hawaiian high chiefs and royalty supposedly had their remains placed in cracks and small caves long this cliff to protect and preserve them. The trail then traverses a couple of 500-foot-deep gulches before descending into Waimanu. The nine-mile (one-way) route takes an entire day, but the long slog provides some phenomenal views of untouched Hawaii complete with feathering waterfalls and, under the right conditions, some monstrous rainbows.

One easy alternate route. You can put in ocean kayaks at nearby Waipio Valley and paddle over. This is for experienced paddlers as the Windward Coast of the Big Island is isolated, wind-ravaged, and capricious when it comes to weather and water conditions. The kayaks are particularly useful for paddling up the heavily birded, meandering stream that runs through Waimanu (and also takes you closer to the waterfalls.

Waimanu itself is home to endangered Hawaiian hoary bats as well as indigenous plants like ohia and rare loulu trees that cling to sheer cliff faces. Down below, Waimanu Stream emerges from several waterfalls at the back of the valley and meanders past hala groves and mango and ulu (breadfruit) trees before arriving at a lonely beach. You can explore the taro lo'i (terraces) and old stone foundations of heiau (temples). While the locals may tell you to beware of nightmarchers (unfriendly ghosts of ancient Hawaiian royalty that supposedly inhabit Waimanu), more likely you will have to watch out for feral pigs.

Check weather conditions before departing to avoid being trapped in Waimanu during a flood. There's a state campground on the shore with nine campsites and several compost toilets, but no potable water (your water purification system needs to handle leptospirosis, which is common in Waimanu). Permits (free) are required, and reservations are recommended, especially from June through August. For reservations, which can be made no more than 30 days in advance, call the Hawaii State Division of Forestry and Wildlife in Hilo, 808-974-4221

—Alex, 07/31/06