After this intersection, SR 71 becomes a freeway up to Rio Rancho Road before reverting to an expressway up to Mission Boulevard.

The route becomes a short freeway for about a mile until it meets at the Kellogg Interchange in San Dimas, where it terminates at I-10 and SR 57.

Just south of the Mission Boulevard exit, all aspects of the highway, such as its alignment, lane width, pavement, barriers, and access, 'upgrade' to freeway standards.

The section of the highway between Corona and Chino is notorious for thick winter fogs at dawn and dusk, resulting in many automobile collisions when drivers fail to slow down due to reduced visibility.

Residents of Los Serranos (now Chino Hills) recall being awakened by sounds of crinkling bumpers, fenders, and headlights.

[7] The route between Claremont/Pomona and Lake Elsinore roughly followed the path of the Butterfield Overland Mail stagecoach line.

When the portion between San Diego and Temecula was redesignated US 395, SR 71 was rerouted to run from Pomona to Aguanga.

[13] Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on a west-to-east alignment (including its original eastern segment that extended through Temecula and Anza), and do not necessarily reflect current mileage.