Below is an excerpt from the list of appointments of U.S. Postmasters, 1832-1971, courtesy of the U. S. National Archives and Records Administration (NARA). It shows the appointment of the first postmaster for El Cajon, Amaziah L. Knox, on June 6, 1878:

Knox, originally from Maine, had come to San Diego County in 1869, where he bought some acreage in the El Cajon Valley and began raising wheat. He also began to take lodgers in his house, which he eventually expanded into a hotel, taking advantage of his location at the half-way point between the city of San Diego and Julian, which was experiencing a boom due to the discovery of gold.

An item in the San Diego Union on of December 9, 1873 reported a visit to the paper’s offices by “Mr.Knox, of Cajon Valley” who reported that heavy rains had made the ground so wet that “they will have to wait awhile before they can go on plowing. Between 5,000 and 6,000 acres will be planted in wheat on the Cajon this season,” the article stated, of which Knox was planting some 2,000 acres.

Within a decade Knox and other valley ranchers would grow an expanding assortment of crops, including grapes, raisins and olives, of sufficient quantity and quality to appeal to markets beyond California. An 1888 book, reporting on the operation of George Cowles, an El Cajon neighbor of Knox, stated that “…today the raisins produced on the Cowles Ranch are sent all over the United States, and they are without doubt superior to any grown either in this country or Europe. ……This season there were shipped from eight to ten thousand boxes of raisins from this vineyard which is but five years old. It is situated in the center of the valley. Besides grapes, and olives, and other fruits, there are about one thousand acres in grain, while the ranch is stocked with one hundred head of fine horses, and about three hundred head of choice, graded cattle.”

While the Post Office Department chose the name El Cajon for the office over which Mr. Knox presided, his home and land were then more widely known as “Knox’s Corner.” But in 1912, just a few years before his death at the age of 84, Amaziah Knox would see the city of El Cajon formally incorporated. One of the members of the first city government would be his son, Dr. Charles Randall Knox. The original Knox house at what is now the southwest  corner of Main Street and Magnolia Avenue in downtown El Cajon is today the home of the El Cajon Historical Society.

Sources for this post included the National Archives and Records Administration, historic San Diego County newspapers, the El Cajon Historical Society, and the following books: Picturesque San Diego by Douglas Gunn, published in 1887, City and County of San Diego Illustrated, and Containing Biographical Sketches of Prominent Men and Pioneers, by Leberthon and Taylor, published in 1888, and City of San Diego and San Diego County: The Birthplace of California, by Clarence Alan McGrew, published in 1922.