Daniel K. Inouye Highway

Daniel K. Inouye Highway is a major cross-island arterial on the Island of Hawaiʻi, connecting the windward and leeward coasts. Designated as Hawaii Route 2000, it traverses the high-elevation saddle between the volcanic peaks of Mauna Loa and Mauna Kea. The highway is named in honor of the late U.S. Senator Daniel K. Inouye, a Medal of Honor recipient and influential figure in Hawaii's modern development.

History and designation

The roadway's origins lie in the historic Saddle Road, constructed by the United States Army in 1942 to link military facilities during World War II. For decades, it remained a narrow, winding, and notoriously hazardous route maintained by the federal government. A major modernization project, a partnership between the Hawaii Department of Transportation and the U.S. Department of Transportation, began in 2004 to realign and reconstruct the highway to modern safety standards. Upon completion of its western segment in 2013, the entire improved corridor was officially renamed by an act of the Hawaii State Legislature to honor Senator Inouye, who had died the previous year and was a pivotal advocate for the project's federal funding.

Route description

Beginning in Hilo, the highway ascends rapidly through the lush Hilo district, passing near the University of Hawaii at Hilo and the Mauna Loa Observatory access road. It crosses the stark, high-altitude volcanic landscape of the island's saddle region, an area used for scientific research including facilities like the NASA Infrared Telescope Facility and the Subaru Telescope. The route offers dramatic views of both Mauna Kea and Mauna Loa, and the climate shifts dramatically from rainforest to arid alpine desert. Descending toward the leeward side, it terminates at a junction with Hawaii Route 190 near Kailua-Kona, providing critical access to the Kona International Airport and the resorts of the Kona Coast.

Major intersections

The entire route is located within Hawaii County. Key junctions from east to west include its eastern terminus at the intersection with Hawaii Route 200 (Kanoelehua Avenue) in Hilo. It intersects the access road to the Mauna Loa Observatory and the John A. Burns Way, which leads to the Mauna Kea summit observatories. The western terminus is a major interchange with Hawaii Route 190 (Mamalahoa Highway) near Kailua-Kona, which provides direct connections to Waikoloa, Waimea, and the Kona International Airport.

See also

* Interstate H-3, another Hawaiian highway named for a prominent political figure * List of Hawaii state highways * Saddle Road (Hawaii), the historic name for the roadway * Transportation in Hawaii

Category:State highways in Hawaii Category:Transportation in Hawaii County, Hawaii Category:Buildings and structures named for Daniel Inouye