Oahu is the third largest of the eight main Hawaiian islands (the others being Maui, Kauai, Molokai, Lanai, Niihau, Kahoolawe and the Big Island of Hawaii.) The largest city on Oahu is Honolulu, which is also Hawaii’s capital city, and ranks as the 11th largest city in the United States. Oahu is known for Waikiki beach and Pearl Harbor. 
Oahu has a total area of 607.7 square miles, with 112 miles of coastline. The island is surrounded by the Pacific Ocean. There are two mountain ranges on the island, Koolau Range in the east and Waianae Range in the west. Between the two mountains is a valley and farmland in which crops are grown, mostly pineapple and sugar cane. Diamond Head, a 760 ft extinct volcanic crater is located at the southeastern end of the island. 
The average temperate in winter months is 72 degrees, and in summer months is 81 degrees. Average annual rainfall ranges from 20 inches in the Waianae area to 158 inches in Upper Manoa Valley.
There is a large transient population due to the thriving tourism industry. Oahu has over 4 million visitors annually. There is also a large military presence on the island. The 875,000 permanent residents comprise a variety of ethnicities, the largest groups include Hawaiian/Part Hawaiian, Caucasian, Japanese, Filipino, Chinese, and mixed ethnicities. 
The University of Hawaii at Manoa has on average over 20,000 students enrolled. There are also 4 Community Colleges on Oahu that are part of the University of Hawaii system. Other higher education facilities on Oahu include a 100 acre campus of Brigham Young University, located 35 miles north of Honolulu,  Chaminade University in Honolulu,  and Hawaii Pacific University. 
Honolulu International Airport is the main airport for the State of Hawaii. It handles both international flights from many major airlines and inter-island flights with Hawaiia's 2 major airlines, Aloha Airlines and Hawaiian Air. The airport is located about three miles west of Downtown Honolulu, and seven miles from Waikiki.