The primary means of traversing the plateaued central part of the island, the route begins running south from a junction with GH-1 and almost immediately curves eastward into Mongmong-Toto-Maite.

It shortly intersects the east end of GH-33, which provides a route into downtown Hagåtña.

A significant amount of the land north of the road was once Naval Air Station Agana, and GH-8 used to be the primary route to the base, but after the Base Realignment and Closure Commission chose to have its operations relocated, the base was closed and the land has been returned to the local government, which has restored the area's original name of Tiyan.

Won Pat International Airport and support industrial operations, so the main road in Tiyan remains an important though unnumbered highway junction.

Towards its east end, GH-8 junctions two other important routes: GH-10 towards Mangilao and the south coast and GH-16 back north towards Tamuning and Dededo.