SR 25 provides access to the Pinnacles National Park east entrance, running parallel to the San Andreas Fault.

Upon reaching Hollister, the route turns into a four-lane undivided road, curving north and west through the east side of the city.

[8] The Airline Highway Association was organized in 1933-4 and was composed of representatives of Alameda, Santa Clara, San Benito, Kern and Kings Counties.

In this sense it is defined as an Americanism dating back to 1805 meaning "traveling a direct route".

[9] Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage.