The Castle Trail is one of the most fabulous trails on O`ahu. It was built with the money of sugar baron James B. Castle in 1906. For the history of the trails construction and usage check this link. HISTORY of CASTLE TRAIL. I don't remember where I down loaded this information or I would give the writer credit. Through the hard work of the officers of the Hawaiian Trail and Mountain Club permission was once again granted to the club to clear and then hike the trail.
Below is a map of the access from the beach and then the trail to the Ko`olau Summit. REMEMBER THIS IS NOT A PUBLIC HIKE. YOU MUST BE A MEMBER OF THE HAWAIIAN TRAIL AND MOUNTAIN CLUB, and CAN ONLY HIKE THE TRAIL ON THE DAY AGREED UPON BY BOTH THE CLUB AND THE BISHOP ESTATE.