Haw. Rev. Stat. § 32
For the purpose of representation in the senate, the Territory is divided into the following senatorial districts, namely:
First senatorial district: That portion of the island of Hawaii known as Puna, Hilo and Hamakua;
Second senatorial district: That portion of the island of Hawaii known as Kau, Kona and Kohala;
Third senatorial district: The islands of Maui, Molokai, Lanai and Kahoolawe;
Fourth senatorial district: That portion of the island of Oahu lying east and south of Nuuanu Street and Pali Road and the upper ridge of the Koolau Range from the Nuuanu Pali to Makapuu Point and all other islands not specifically enumerated;
Fifth senatorial district: That portion of the island of Oahu lying west and north of the fourth senatorial district; and
Sixth senatorial district: The islands of Kauai and Niihau.
HRS § 32