Mexico 3 stretches southeast 198 kilometers (123 mi) from Ensenada to San Felipe on the Sea of Cortez. The first two-thirds of the highway traverses high chaparral along the gradually ascending western slopes of the Sierra Juárez.

Just past Km 39 is a short paved road leading north into Ojos Negros, a small farming center with a Pemex station (which more often than not pumps gas from a can), as well as several markets, an auto parts dealer, and a pharmacy.

A natural spring flows from a steep hillside on the east side of the highway between Km 73 and 74—a good place to stock up on drinking water.