In 1940, Benjamin Parker School was a founding member of the Rural O‘ahu Interscholastic Association (ROIA – with Kahuku, Leilehua, Waialua and Waipahu.)

Parker began bursting at the seams … “Congestion and inadequate accommodations at Benjamin Parker School in Kaneohe, was disclosed Thursday in a letter to the Mayor and board of supervisors by Joseph T Ferreira, of the department of public instruction, who has asked for the installation of three Quonset huts to relieve the conditions.” Castle High School was founded in 1951.

On “January 2, 1951, Principal Clinton Kanahele and his 700 students of Benjamin Parker Elementary and High School made their move to the new Benjamin Parker Annex on Kāne‘ohe Bay Drive.” “During the first year of operation, approximately 750-students enrolled in grades 7-12.

In June, 1952, 108-seniors made up the first graduating class of the James B Castle Intermediate and High School.

Castle High School is located in Kaneohe, on the Windward side of the island of Oahu.

Currently, 42% of the school population qualify for the federally assisted free or reduced lunch program.

Additionally, 6% go to business or trade school, 2% enroll in a military service, and the remaining 12% find employment.

Castle High was accredited in 2011 by the Western Association of Schools and Colleges for a period of 6 years, and adopted School-Community-Council in place of School/Community Based Management (SCBM).

The high school also has an internationally recognized performing arts program, Castle Performing Arts Center, or "CPAC" has produced multiple shows which have been the Hawaii premiere of those shows and participated in the 2009 Fringe Festival in Edinburgh, Scotland.