In the early days when a stage station was run at this place by Darrel Duppa, the location was known as Agua Fria. The post office for Agua Fria was discontinued in 1895. According to post office rules, an office couldn't reopen under its old name.  Therefore, when the post office was re-established in 1898, the name Dewey was selected. There is some question as to whether it was named for Rear Admiral Dewey or for a pioneer settler in the vacinity. It is to be noted also that the name of the railroad station was and still is Cherry Creek, but this name was in use elsewhere as a post office, and so couldn't be used.

Source: Arizona Department of Commerce

Scenic Attractions:

Dewey-Humboldt is located 15 miles east of Prescott. It is interesting to note that the area had been known as the "Tri-City" area referring to Prescott, Chino Valley and Prescott Valley. Now that Dewey-Humboldt has been incorporated, the proper term is the "quad-cities".