The importance of the orange in California fruit culture is shown in the number of places which have been named for it, including at least seven communities or settlements.

The town of Orange laid out by Glassell Chapman in the 1870s, was first called Richland; then its name was changed to Orange because there was another Richland in Sacramento County (Santa Fe). The Land Office Map of 1879 shows neither name, but Orange post office was established September 1873. It is assumed that the name was chosen to accent the developing range culture in the district. However, it is also possible that it is a transfer name from the East. Andrew Glassell, one of the founders of the town, was a native of Virginia, where in the early 1700 a county had been named Orange in honor of the son-in-law of King George II.

By 1880, there were Orange counties in six other states, as well as numerous towns and post offices so named. The California County, carved from Los Angeles County on March 11, 1889, to be sure, was named because the orange industry flourished there. "This county was given its name by the Legislature because of the orange groves for which it is justly famous" (Blue Book 1907, pg. 278).

August 5, 1889, Orange County adopted a seal consisting of an orange with stem and three leaves. A design by Laura Shernaman, embodying the present seal, surrounded by a flaming yellow sun on an orange background, became the official County flag in 1968.