San Geronimo, California
23 topographic sheets cover this place, the earliest surveyed in 1914 and the latest in 1983. It stands in the Northwest Marin census division. It lies in ZIP code area 94963. It lies near Green Hill. The Survey maps it on the San Geronimo quadrangle. 510 people lived here at the 2020 count. It stands 292 feet above sea level.
Then and now
1914 to 1983The same ground, surveyed 69 years apart. Drag the handle to wipe between them. Both sheets are United States Geological Survey originals; neither has been altered.


Population over time
2 figuresSan Geronimo grew from 446 to 510 between 2010 and 2020. These are the recorded population figures Wikidata holds for this place, reached through the Geographic Names Information System number this page is keyed on rather than by name, so they belong to this place and not to another of the same name. Most are census counts, but not all are: an early figure may be a founding or settlement estimate, and an estimate published within five years of a census is left out. The change column is computed, and is left blank where more than 20 years separate a figure from the one before it, because a gap that long is not a change between two counts.
| Year | People | Change |
|---|---|---|
| 2010 | 446 | |
| 2020 | 510 | +64 (+14%) |
Topographic sheets covering this place
10 surveys from 23 printed sheetsMatched by testing this settlement's coordinate against the published boundary of every sheet in the United States Geological Survey's historical collection. Each opens the scanned sheet at the Survey.
- 1914 USGS Petaluma quadrangle1:62500, 5 printings
- 1942 USGS Petaluma quadrangle1:62500
- 1947 USGS Santa Rosa quadrangle1:250000
- 1949 USGS Santa Rosa quadrangle1:250000, 2 printings
- 1954 USGS Petaluma quadrangle1:62500, 3 printings
- 1954 USGS San Geronimo quadrangle1:24000, 5 printings
- 1958 USGS Santa Rosa quadrangle1:250000, 3 printings
- 1962 USGS Santa Rosa quadrangle1:250000
- 1964 USGS Santa Rosa quadrangle1:250000
- 1983 USGS Napa quadrangle1:100000
Fires near this place
44 since 1992Regional context, not property-specific evidence. The federal wildfire occurrence database lists 44 fires within 5 miles of San Geronimo between 1992 and 2020, burning about 299 acres in total. None started naturally. 2 were recorded as arson. Distance is straight-line from the map coordinates, so a fire counted here may appear on a neighbouring settlement's page as well.
| Reported cause | Fires |
|---|---|
| Missing data/not specified/undetermined | 22 |
| Equipment and vehicle use | 10 |
| Power generation/transmission/distribution | 5 |
| Misuse of fire by a minor | 3 |
| Arson/incendiarism | 2 |
| Recreation and ceremony | 1 |
| Debris and open burning | 1 |
The most recent of them, most recent first, with the day each was reported and the service that recorded it.
| Date | Cause | Size | Reported by | Name on the report |
|---|---|---|---|---|
| 8 September 2004 | Arson/incendiarism | under an acre | Point Reyes National Seashore | RANDALL |
| 29 September 2014 | Missing data/not specified/undetermined | 1.0 acres | Marin County Fire Department | not named |
| 26 September 2007 | Equipment and vehicle use | under an acre | California Department of Forestry & Fire Protection | not named |
| 24 September 2014 | Missing data/not specified/undetermined | under an acre | Marin County Fire Department | not named |
| 21 September 2010 | Equipment and vehicle use | under an acre | Marin County Fire Department | not named |
| 2 September 2006 | Equipment and vehicle use | under an acre | California Department of Forestry & Fire Protection | not named |
| 18 September 2002 | Power generation/transmission/distribution | under an acre | Point Reyes National Seashore | TEIXERA |
| 17 September 2011 | Misuse of fire by a minor | under an acre | Marin County Fire Department | not named |
Settlements close enough to share some of these fires:
Mines and quarries near this place
10 of 13 shownRegional context, not property-specific evidence. The federal mineral resources record lists 13 workings within 5 miles of San Geronimo: 9 occurrences, 1 past producer, 1 unknown, 1 prospect. 1 still produces. What was taken out: Copper, Stone, Crushed/Broken, Manganese, Gold. Distance is straight-line from the map coordinates, so a quarry counted here may appear on a neighbouring settlement's page as well.
| Where | Site | Commodity | Status | Recorded |
|---|---|---|---|---|
| Maillard Ranch | Chromium | Occurrence | ||
| McKinnan Gulch | Copper, Lead | Occurrence | Vein | |
| Union Gulch | Copper, Silver, Gold | Past Producer | 1863 | |
| Union Gulch | Copper, Gold, Silver | Unknown | ||
| Unnamed Location | Gemstone | Occurrence | ||
| Lafranchi Quarry | Stone, Crushed/Broken | Producer | ||
| Maillard Ranch | Manganese | Occurrence | ||
| Maillard Ranch | Manganese | Occurrence | ||
| San Geronimo | Gold | Occurrence | ||
| San Geronimo | Gold | Prospect |
Storms near this place
1 since 2019Regional context, not property-specific evidence. The National Weather Service names San Geronimo in 1 storm report in 2019: 1 flood. No death or injury is recorded in these reports. Each account below is quoted exactly as the forecast office filed it, from the NOAA Storm Events Database, and each date opens the federal record of that event.
| When | Event | Place named | Harm | What the report says |
|---|---|---|---|---|
| February 2019 | Flood | San Geronimo | - | Water across roadway at Nicasio Valley Rd and San Geronimo Valley Dr, also tree down blocking entire roadway. |
Nearest settlements
The eight closest, with where each one stands in the county. Distances are straight-line, computed from the Geographic Names Information System coordinates.
| Map | Place | Distance | Sheets |
|---|---|---|---|
| Woodacre | 1.0 miles | 23 | |
| Forest Knolls | 1.3 miles | 23 | |
| Mailliard (historical) | 1.6 miles | 23 | |
| Lagunitas | 2.0 miles | 23 | |
| Shafter | 2.4 miles | 23 | |
| Bothin (historical) | 2.5 miles | 24 | |
| Irving (historical) | 3.2 miles | 23 | |
| Nicasio | 3.8 miles | 23 |
Elsewhere
Matched on this settlement's Geographic Names Information System number rather than its name, so it cannot be a different place of the same name in another state.
| Wikipedia article on San Geronimo | An encyclopaedic summary. Its text is share-alike, so it is linked here rather than copied. |
| Wikidata item Q2075091 | The structured record the population and elevation above come from. Public domain (CC0). |
Provenance
This settlement is recorded in the Geographic Names Information System as feature 232399. The sheet list is computed by point-in-boundary test against the United States Geological Survey's historical topographic inventory. Both are works of the United States government and carry no copyright under 17 U.S.C. 105.
Wildfire. Short, Karen C. 2022. Spatial wildfire occurrence data for the United States, 1992-2020 [FPA_FOD_20221014]. 6th Edition. Fort Collins, CO: Forest Service Research Data Archive. https://doi.org/10.2737/RDS-2013-0009.6 Collected with United States Government funding and usable without additional permissions or fees.
Mines and quarries. USGS Mineral Resources Data System (MRDS) https://mrdata.usgs.gov/mrds/ A work of the United States government, no copyright under 17 U.S.C. 105.
Storms. NOAA National Centers for Environmental Information, Storm Events Database https://www.ncei.noaa.gov/stormevents/ A work of the United States government, no copyright under 17 U.S.C. 105. Narratives are quoted verbatim from the National Weather Service report and are not edited or summarised.









