Charles Martin first homesteaded the area in 1851 and operated a tollgate and station for stagecoaches crossing the mountains.

[3] Glenwood was a stop on the narrow gauge South Pacific Coast Railroad (SPC), which began service from Alameda (north terminus, with a ferry to San Francisco) to Felton in 1880.

To minimize length and steepness, six tunnels were dug through ridges of the Santa Cruz Mountains.

The April 18, 1906 San Francisco earthquake twisted some of the rails and damaged bridges and tunnels along the line.

Mrs. Margaret Koch, a well-known local-history author and great-granddaughter of founder Charles Martin, served as Glenwood's last postmistress.