The Hawaii-California Training and Testing Study Area consists primarily of the Hawaii Study Area, the California Study Area, and the transit corridor connecting the two. The Study Area includes the at-sea components of various range complexes, Navy pierside locations and port transit channels, bays, harbors, inshore waterways, amphibious approach lanes, and civilian ports where training and testing activities occur.

The at-sea ranges off Hawaii and California are vital in supporting military readiness. They have unique attributes, including location, proximity to nearby installations, environment, infrastructure, and size, that make them an ideal setting for training military personnel and testing equipment and systems.