SR 177 begins at I-10 near Desert Center and briefly travels north, intersecting with CR R2.

At this intersection, SR 177 turns northeast and travels across the Mojave Desert, through the Chuckwalla Valley.

The highway passes along the southeastern boundary of Joshua Tree National Park before turning due north and crossing the desert for several miles.

[7] The Metropolitan Water District built a road from Desert Center that ran north before turning east to Earp along with portions of the Colorado River Aqueduct from February 20 to August 4 in 1933.

[4] Except where prefixed with a letter, postmiles were measured on the road as it was when the route was established, based on the alignment that existed at the time, and do not necessarily reflect current mileage.