The valley is bisected roughly east-to-west by Sir Francis Drake Boulevard; a number of streets in the towns along this road were constructed on the former right-of-way of the Northwestern Pacific Railroad.

The San Geronimo Valley derives its name from the San Geronimo Ranch, established by Adolph Mailliard and Ann Eliza Ward in 1868, where they bred thoroughbred horses, including the famous stallion Monday, who sired most of the race horses in California.

Each elementary program (Open Classroom, Montessori-inspired) has its own unique philosophy and pedagogical methods, all working within the framework of the California professional and academic standards.

Woodacre is home to Spirit Rock Meditation Center, dedicated to the teachings of Buddha and Vipasannā mediation; Dickson Ranch, and the Marin County Fire Department headquarters.

San Geronimo Valley also comprises the greater part of the Lagunitas Watershed, in which some of the last remaining coho salmon spawn.