The Post Office was established in 1895 at the Southern Pacific Depot and run by Mr. Nathaniel Brittan. As the town grew it eventually moved to four different locations to accommodate its business.
During 1926, 20-year-old Mary Kay Davis began the $60 per month job as San Carlos’s first postmaster. As a requirement for the job, Mrs. Davis had to provide a post office. Using money she and her husband had saved, she had a small post office built in front of her home in the 700 block of El Camino Real. As the population increased, the post office moved three times to larger quarters before settling at its present site at 809 Laurel Street.
Also in 1926, the phone company built an $11,000 building in the 500 block of Laurel Street. In that same year, Southern Pacific built a spur track servicing San Carlos.