The route continues mauka[colloquialism] along Waiānuenue Avenue to a little over a half-mile past the mile 1 where it veers left onto Kaūmana Drive near Gilbert Carvalho Park.

[4] Starting at the “Y” junction adjacent to Gilbert Carvalho Park, Highway 200 continues mauka (uphill) on Kaūmana Drive and provides access to neighborhoods overlooking Hilo.

Mauna Kea Observatory on the summit, an ideal location for astronomical seeing, is under the jurisdiction of the University of Hawaiʻi Institute for Astronomy.

West and northwest of these turnoffs, the 6.5-mile (10.5 km) segment of Route 200 from milepost 28 to 35 was dedicated and opened to traffic on May 29, 2007, with Senator Daniel K. Inouye as the keynote speaker and other local dignitaries.

The new section was constructed to full federal highway standards, with wide shoulders, rumble strips, good signage and emergency phones at regular intervals.

From milepost 35 to 44 the road passes the main gates of Pōhakuloa Training Area and Bradshaw Army Airfield before continuing across the military reservation.

[8] This new section avoids the old route, where from milepost 44, near Kilohana, to the Māmalahoa Highway the road retained its original character, a narrow ribbon of poorly maintained pavement with crumbling edges.

It is common for drivers to negotiate the center of the road to avoid the rough shoulders, moving back into the lane only when necessary to pass traffic proceeding in the opposite direction.

The route is quite scenic with views of the coastline, the Hualālai and Kohala volcanoes, winding its way across Parker Ranch and through the development of Waikiʻi.

Using prison labor, it started near Holualoa Bay at 19°35′57″N 155°58′26″W / 19.59917°N 155.97389°W / 19.59917; -155.97389 (Judd Road west) and proceeded in a straight line up to the plateau south of Hualālai.

After ten years only about 12 miles (19 km) were completed, when work was abandoned at 19°38′38″N 155°45′12″W / 19.64389°N 155.75333°W / 19.64389; -155.75333 (Judd Road east) when the 1859 eruption of Mauna Loa blocked its path.

While planning for the defense of the Hawaiian Islands in the wake of the attack on Pearl Harbor, the U. S. Army hastily built an access road in 1943 across the Humuʻula plateau[11] of Parker Ranch at 19°41′44″N 155°29′8″W / 19.69556°N 155.48556°W / 19.69556; -155.48556 (Humu‘ula Saddle).

Following the end of World War II in 1945, the Army turned over jurisdiction of the road to the Territory of Hawaiʻi and it was designated "State Route 20".

About the same time, Tom Vance, who had earlier supervised building a highway up Mauna Loa named for Governor Ingram Stainback, secretly used his prison laborers to start a more direct Hilo-Kona road.

Completion of these projects represent a major realignment of island traffic patterns and conversion of this notorious roadway into a modern state highway.