Punahou School, once known as Oahu College, is a private, co-eucational, nonsectarian college preparatory school located in Honolulu in the U.S. State of Hawaii. With about 3,700 students attending the school, in kindergarten through the twelfth grade, it is the largest independent school in the United States. In 2006, Punahou School was ranked as the nation's "greenest" school in America.The student body is diverse, with student selection based on both academic and non-academic considerations. In 2008, its sports program is ranked by Sports Illustrated as the best in the country out of 38,000 high schools.