Station ALOHA is a deep water (~4,800 m) location approximately 100 km north of the Hawaiian Island of Oahu.  Thus, the region is far enough from land to be free of coastal ocean dynamics and terrestrial inputs, but close enough to a major port (Honolulu) to make relatively short duration (less than five days) near-monthly cruises logistically and financially feasible. Sampling at this site occurs within a 10 km radius around the center of the station.
Each HOT cruise begins with a stop at a coastal station south of the island of Oahu, approximately 10 km off Kahe Point (21° 20.6N, 158° 16.4W) in 1500 m of water. Station Kahe (termed Station 1) is used to test equipment and train new personnel before departing for Station ALOHA.  Since August 2004, Station ALOHA has also been home to a surface mooring outfitted for meteorological and upper ocean measurements; this mooring, named WHOTS (also termed Station 50), is a collaborative project between Woods Hole Oceanographic Institution and HOT.  WHOTS provides long-term, high-quality air-sea fluxes as a coordinated part of HOT, contributing to the program’s goals of observing heat, fresh water and chemical fluxes.  In 2011, the ALOHA Cabled Observatory (ACO) became operational.  This instrumented fiber optic cabled observatory provides power and communications to the seabed (4728 m).  The ACO is currently configured with an array of thermistors, current meters, conductivity sensors, two hydrophones, and a video camera.