The turn of the 20th century saw the layout of the initial town streets.
 While "Old County Road" east of the railroad track had been in use as a stage line since at least 1850, the present-day layout west of the railroad track was constructed in the first years of 1900.
 Cedar, Elm, Laurel, Magnolia, Maple (renamed El Camino Real) and Walnut were put down in this time.

Growth remained slow through the first fifteen years of the new century, but in 1918 the town had grown enough to build a school at 600 Elm Street.
 One year previously Frederick Drake ("The Father of San Carlos") had purchased 130 acres (53 hectares) of real estate in San Carlos in foreclosure, and began marketing it.
 Growth came quickly, and the early 1920s saw Drake build an office at the southwest corner of Cypress (now San Carlos Ave) and El Camino Real, which is still existent, and as of May 2013 is home to an AT&T Cellular store.

In the early 1920s, the cypresses along Cypress Ave.
were removed, and the street widened and renamed San Carlos Ave.
 In 1923 the growing municipality founded a fire station, and in 1925 the founders voted to incorporate.

The Great Depression affected families in San Carlos, as it did everywhere, but growth continued, and population grew from approximately 600 at incorporation in 1925 to 5,000 in 1941.

While services such as stores increased in this period, by the beginning of World War II San Carlos was still known in the Bay Area as a rural community.
 Most of the land in the municipality was still used for agricultural purposes, and photographs of the time show a landscape with few houses separated by large fields.
The turn of the 20th century saw the layout of the initial town streets.  While "Old County Road" east of the railroad track had been in use as a stage line since at least 1850, the present-day layout west of the railroad track was constructed in the first years of 1900.  Cedar, Elm, Laurel, Magnolia, Maple (renamed El Camino Real) and Walnut were put down in this time.
Growth remained slow through the first fifteen years of the new century, but in 1918 the town had grown enough to build a school at 600 Elm Street.  One year previously Frederick Drake ("The Father of San Carlos") had purchased 130 acres (53 hectares) of real estate in San Carlos in foreclosure, and began marketing it.  Growth came quickly, and the early 1920s saw Drake build an office at the southwest corner of Cypress (now San Carlos Ave) and El Camino Real, which is still existent, and as of May 2013 is home to an AT&T Cellular store.
In the early 1920s, the cypresses along Cypress Ave. were removed, and the street widened and renamed San Carlos Ave.  In 1923 the growing municipality founded a fire station, and in 1925 the founders voted to incorporate.
The Great Depression affected families in San Carlos, as it did everywhere, but growth continued, and population grew from approximately 600 at incorporation in 1925 to 5,000 in 1941.
While services such as stores increased in this period, by the beginning of World War II San Carlos was still known in the Bay Area as a rural community.  Most of the land in the municipality was still used for agricultural purposes, and photographs of the time show a landscape with few houses separated by large fields.
San Carlos, California