The top reported proficiency rate is 67% in Science. The lowest is 47% in Math.
Original Research by School Decision on San Geronimo Valley Elementary
San Geronimo Valley Elementary sits at the end of a long, forested corridor in western Marin County, on a shared campus straddling a small creek at One Lagunitas School Road. The school is part of the Lagunitas Elementary district, which serves the four small unincorporated towns of the San Geronimo Valley. The campus itself is physically connected to a companion campus and, publicly reported, linked by a short bridge over the creek. The San Geronimo Valley Community Center, attached to the district grounds, functions as the civic gathering place for the valley, hosting a food bank and community programming.
The school is very small, serving kindergarten through sixth grade, with sixth grade carrying no enrollment in the most recent data. Each grade cohort is a handful of children. That scale shapes everything: class sizes are tight, peer groups are stable from year to year, and the social world of a student here is narrow and consistent. The student body is predominantly white, with a smaller Hispanic share and a multiracial group rounding out most of the remaining enrollment. A modest share of students qualify for free or reduced-price lunch, which is on the lower end for a California elementary school. Data on English learner status and students with IEPs was not available in the data provided.
The district underwent a substantial structural change in 2023. It had long offered two distinct elementary programs, an Open Classroom and a Montessori program, as separate pathways. The school board voted to consolidate them into a single combined TK-8 program, publicly reported as the Lagunitas Community School, organized around a community-school philosophy with wraparound services. The standalone Open Classroom, which had run for many years, no longer exists. A family drawn here specifically by one of those two original models will find a blended successor, and a parent may want to discuss directly with the school how that philosophy is expressed in daily instruction today.
On state assessments, the picture is uneven. The school is tested in grades three through five on the California CAASPP, and results vary meaningfully by grade and subject. Fifth-grade ELA proficiency is the clear high point, well above the majority of students reaching the bar. Fifth-grade math and science also show solid results. Third and fourth grade are weaker in both ELA and math, with fourth-grade math in particular sitting at the lower end of what the school produces. Taken across all tested grades and subjects, the school's overall proficiency index falls below the midpoint among districts in Marin County, based on the comparison set of county districts. That said, the cohort sizes at this school are very small, meaning year-to-year swings in a single grade can move the aggregate numbers considerably. Only one year of data is available, so trend direction cannot be established.
No program offerings data was available in the data provided. Given the school serves only through sixth grade, graduation rates do not apply here, and no high school pathway data is relevant.
Housing in this zip code is among the most expensive in the state, sitting dramatically above the California median and several times the national median. Rental data was not available. At current mortgage rates, buying into this market carries a monthly cost that would be out of reach for most households. The valley has been deliberately anti-growth for decades: a conservation easement now permanently protects the former golf course land as public open space, no significant new housing is in the pipeline, and development on private parcels is tightly constrained. This is not a place where supply is likely to expand.
Getting around requires a car. Sir Francis Drake Boulevard is the single arterial through the valley, and while a transit route connects the valley to Fairfax and San Rafael, service is infrequent. Shops and services are largely in Fairfax and neighboring Woodacre rather than in San Geronimo itself.
Property owners should be aware that the district's parcel tax, Measure A, was renewed by voters in early 2026 and publicly reported provides more than a substantial share of the district's operating budget. The tax funds teacher salaries, classroom aides, libraries, and arts and music programs. A senior exemption is available.
See more original research from School Decision →