Hawaii is divided into five counties: Hawaiʻi, Honolulu, Kalawao, Kauaʻi, and Maui.

Honolulu County, despite being centralized, administers the outlying Northwestern Hawaiian Islands.

[2] An island in this sense may also include much smaller and typically uninhabited islets, rocks, coral reefs, and atolls.

Some of these are too small to appear on maps, and others, such as Maro Reef, only appear above the water's surface during times of low tide.

All the islands west of Niʻihau—those categorized as the Northwestern Hawaiian Islands—are unpopulated and recently incorporated into the Papahānaumokuākea Marine National Monument.

The islands are the exposed peaks of a great undersea mountain range known as the Hawaiian–Emperor seamount chain, formed by volcanic activity over a hotspot in the Earth's mantle.

The archipelago formed as the Pacific plate moved slowly northwestward over a hotspot in the mantle at about 32 miles (51 km) per million years.

The islands in the northwest of the archipelago are older and typically smaller, due to longer exposure to erosion.

Download coordinates as: Known officially as the City and County of Honolulu, the county includes both the urban district of Honolulu (the state's largest city and capital) and the rest of the island of Oʻahu, as well as several minor surrounding islands.

The county also administers the Northwestern Hawaiian Islands with the exception of the federally governed Midway Atoll.

It is one of the northwesternmost islands, located 161 miles (259 km) east of the International Date Line.

Because of its strong military history, Midway Atoll is classified as a Minor Outlying Island, an unorganized territory of the United States and is therefore not under the jurisdiction of Hawaii.

At 13.21 sq mi (34.2 km2), it is the smallest county by land area in the United States and is often omitted from maps.

With a population of 90, Kalawao County occupies a tiny 13.21 sq mi (34.2 km2) portion on the northern shore of the island.