On July 24, 2018, the National Marine Fisheries Service (NMFS) published a final rule in the Federal Register designating critical habitat for the Main Hawaiian Islands insular false killer whale distinct population segment. The rule becomes effective on August 23, 2018.

The designation, made pursuant to section 4 of the Endangered Species Act, stemmed from litigation brought by the Natural Resources Defense Council against the Secretary of Commerce and which resulted in a settlement agreement specifying a time frame for the submission of a final rule.

The designation covers 17,564 square miles of marine habitat surrounding the main Hawaiian Islands. Within the designated area, fourteen areas were excluded, one at the request of the Bureau of Ocean Energy Management, and thirteen at the request of the Navy. No unoccupied areas were proposed for designation as critical habitat.