Castroville was founded in the year of 1863 by Juan Bautista Castro. General Manuel Castro and Juan Battista Castro, two brothers fell heir to 11 leagues of land East of Tembladero Slough. Several thousand acres West of Tembladero Slough went to Juan B. Cooper who eventually moved to San Francisco.
In the year 1863 the first business was a grocery store opened by Juan Pomber. The building is still occupied today as a restaurant, on the West side of Merritt Street, between Speegle and Preston Streets. Also in that year a flour mill was opened.

In the year 1865 Dr. Martin built and operated the first hospital in Monterey County. Also in that year a dry goods stores was opened, Wells Fargo Express Company established an office and the first Post Office was opened.

On the corner of Preston and McDougal, across from the town square, was erected the first hotel in Castroville, a two-story building called the Plaza Hotel.  

Juan B. Castro donated the land for the town square and also for the cemetery, which is located in Moss Landing.

The building on he Northwest corner of Speegle & Merritt, known as the I.D.E.S. Hall, was a stage coach stop in the early days before the railroads arrived. About 1870, on the Southwest corner of Speegle and Marritt Street, two brick buildings were built, one by Henry Mean and Manuel Merritt and the other by Juan B. Cooper. These buildings are still being used. Also about this time Juan B. Cooper built the two-story dwelling on the Northeast corner of Speegle& Merritt Street, where he raised his family.

During the 1870’s the town had a brick yard and a brewery. In 1889 the flour mill burned down on a Sunday morning. There were 11 saloons in town and two at the depot a total of 13 at one time.
In 1869 the building which is known

as the McCarthy Hardware was the first school house built in Castroville. The location was 4 blocks east of Merritt Street, North side of  Preston.

Castroville had the first roundhouse for Southern Pacific Railroad. Here is where they changed crew and repaired engines and railroad cars. The first master mechanic at the roundhouse was a man by the name of Charles Hunter. Passenger trains would stop in Castroville 20 minutes for lunch. The Southern Pacific had a hotel at the depot, managed by a man named Coates. In 1905 the Southern Pacific Hotel was moved to Tracy, California. There is today, in the Palace of Fine Arts in Washington, D.C. a painting of the Town of Castroville, which was placed there with the honor of being at that time most real Western town in the United States.