The park's name originates from the Hawaiian language words ke kaha kai which translate to "the shore line" in English.

[6] The marsh is known as ʻŌpaeʻula Pond (Hawaiian for "red shrimp") and was the site of a small fishing village that was wiped out in the 1946 tsunami.

[7] The 12 acres (4.9 ha) of wetland provide one of the last remaining nesting grounds of the āeʻo (Hawaiian stilt, Himantopus mexicanus knudseni), the ʻalae keʻokeʻo (Hawaiian coot, Fulica alai),[8] and the only known breeding area for the ʻaukuʻu (black-crowned night heron, Nycticorax nycticorax hoactli) in Hawaii.

Mahaiʻula Bay is accessed by an unpaved lava road which heads west off the main highway a short distance north of the airport.

[1] A 4.5 mi (7.2 km) section of the historic Ala Kahakai coastal trail connects Mahaiʻula and Kua Bay.