Honolulu Harbor, also called Kulolia and Ke Awa O Kou, is the principal seaport of Honolulu and the State of Hawaiʻi in the United States. It is from Honolulu Harbor, located on Mamala Bay, that the City & County of Honolulu was developed and urbanized, in an outward fashion, over the course of the modern history of the island of Oʻahu. Surrounding Honolulu Harbor is downtown Honolulu.

Honolulu Harbor is administered by the Hawaiʻi State Department of Transportation Harbors Division. Honolulu Harbor handles over 11 million tons of cargo annually. The services that the harbor provides are crucial as Hawaiʻi imports over eighty percent of its required goods.

Archaeological surveys conclude that the area around Honolulu Harbor was bustling with human activity prior to 1100. The first European vessel to enter Honolulu Harbor was HMS Butterworth in 1794, a British ship commanded by Captain William Brown. Sailors aboard the ship dubbed the harbor Brown's Harbor to their captain's dismay. Captain Brown insisted that the harbor be called Fair Haven. Fair Haven is synonymous in meaning to the Hawaiian name for the region Honolulu.

Honolulu  /hoʊnoʊˈluːluː/ is the capital and the most populous city of the U.S. state of Hawaii. Honolulu is the southernmost major U.S. city. Although the name "Honolulu" refers to the urban area on the southeastern shore of the island of Oahu, the city and county government are consolidated as Honolulu County which covers the entire island. For statistical purposes, the U.S. Census Bureau recognizes the urban part of Honolulu as a census-designated place. Honolulu is a major financial center of the islands of the Pacific Ocean. The population of the census-designated place was 337,256 at the 2010 census, while the population of the city and county was 953,207. Honolulu is the most populous state capital relative to state population.

In the Hawaiian language, Honolulu means "sheltered bay" or "place of shelter". The old name is said to be Kou, a district roughly encompassing the area from Nuuanu Avenue to Alakea Street and from Hotel Street to Queen Street which is the heart of the present downtown district. The city has been the capital of the Hawaiian islands since 1845 and gained historical recognition following the Japanese attack on Pearl Harbor near the city on December 7, 1941, and as the birthplace of Barack Obama, the 44th and current President of the United States.