Old Mamalahoa Highway

Old Mamalahoa Highway, Big Island

The Old Mamalahoa Highway on the Big Island's Hamakua Coast is a narrow and winding coastline road that begins about 5 miles (8 km) north of Hilo. The 4-mile (6.4 km) stretch until the Hawaii Tropical Botanical Garden are breathtaking. The vegetation is very lush and there is a great lookout point along the way, right before you reach the botanical garden. It overlooks Onomea Bay and the surrounding rainforest.

Key Features

Short rainforest drive north of Hilo

Narrow, winding road with shaded curves and small bridges

Passes through the Onomea area on Hawaii Island's Hamakua side

Access road for Hawaii Tropical Botanical Garden

Views toward Onomea Bay from select roadside areas

Lush vegetation, mossy rock walls and old-road character

Close to Papaikou, Pepeekeo and Hilo

Limited safe pullouts, so avoid stopping on narrow shoulders

Rain can make the pavement slick and visibility lower

Best approached as a slow scenic drive, not a fast shortcut

Frequently Asked Questions

Why is the road called Old Mamalahoa Highway?

The name connects with Mamalahoa Highway, the older road system that served many Hamakua communities before faster modern highway sections carried most through traffic.

What makes this road different from Highway 19?

Highway 19 is the faster main road. Old Mamalahoa Highway is slower and closer to the landscape, with tighter curves, shaded rainforest, small bridges, local homes and short openings toward Onomea Bay.

Why is Onomea Bay often mentioned with this drive?

The road passes above the Onomea area, where rainforest slopes drop toward a rocky bay. The contrast between dense greenery and blue water is one of the most photographed details along the drive.

Is Hawaii Tropical Botanical Garden part of the drive?

The garden entrance is along Old Mamalahoa Highway, and many visitors drive this section before or after walking through the garden's rainforest trails, stream areas and ocean-view plantings.

What photo details stand out along Old Mamalahoa Highway?

Look for mossy rock walls, overhanging trees, narrow pavement, bridge railings and brief views toward Onomea Bay. The greenery is especially vivid after light rain.