Below is a good example of the varied origins of place names in San Diego County. It’s part of a column from the San Diego Union of August 25, 1886.
Nestor A. Young was elected to the state assembly from San Diego County from 1887 to 1893. He also served as a member of San Diego’s first harbor commission. By the late 1890s he’d moved on to the Los Angeles area where, among other things, he sold real estate. But his time living in the area near San Diego’s border with Mexico led to the creation of a community that took his first name. Nestor was an independent ranching town until it was annexed by the city of San Diego in 1957.
James Peebles Marshall Rainbow didn’t get elected sheriff in that 1887 campaign, but he did serve two terms on the county board of supervisors from 1882 to 1884 and from 1891 to 1895. He also was a fruit grower and leader of the little community that grew around his ranch in the valley near Fallbrook which still bears his name.
Sources for this post included historic San Diego and Los Angeles newspapers, the 1890 book An Illustrated History of San Diego County, by the Lewis Publishing Company, and the 2005 book, San Diego County Place Names A to Z, by Leland Fetzer.