| S.N. | County | FIPS Code | County Seat | Est. | Island(s) | Population | Area (sq mi) | Area (km2) |
|---|---|---|---|---|---|---|---|---|
| 1 | Hawaii County | 1 | Hilo | 1905 | Hawaiʻi | 201,513 | 4,028 | 10,432 |
| 2 | Honolulu County | 3 | Honolulu | 1905 | Oʻahu and the Northwestern Hawaiian Islands (except Midway Atoll.) | 974,563 | 597 | 1,546 |
| 3 | Kalawao County | 5 | 1905 | The Kalaupapa Peninsula on Molokaʻi | 86 | 5.2 | 13 | |
| 4 | Kauai County | 7 | Lihue | 1905 | Kauai, Niʻihau, Lehua, and Kaʻula | 72,293 | 622 | 1,611 |
| 5 | Maui County | 9 | Wailuku | 1905 | Maui, Kahoʻolawe, Lānaʻi, Molokai (except the Kalaupapa Peninsula), and Molokini | 167,417 | 1,120 | 2,901 |
