Nicasio, CA— fire, flood & earthquake hazard information
Nicasio is a unincorporated community in Marin County in the San Francisco Bay Area, covering about 1.3 square miles. This page summarizes what official government maps show for Nicasio: CAL FIRE fire hazard severity zones, FEMA flood zones, state seismic hazard zones, dam inundation areas, airport noise contours, and air-quality indicators. Figures are the share of Nicasio’s area that falls inside each mapped zone.
View Nicasio on the interactive map → to check any specific address, free.
Wildfire hazard severity zones
Per CAL FIRE's Fire Hazard Severity Zone maps, 3% is in a High zone, 97% is in a Moderate zone. The remainder of its area is outside currently designated zones.
| High severity zone | 3% |
| Moderate severity zone | 97% |
FEMA flood zones
6% of Nicasio lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO). Federally backed mortgages in a Special Flood Hazard Area generally require flood insurance.
| Special Flood Hazard Area (100-yr) | 6% |
Earthquake faults & seismic zones
The nearest mapped fault, the San Andreas fault zone, is about 4.9 mi (7.8 km) from the center of Nicasio.
| Nearest mapped fault | San Andreas fault zone — 4.9 mi (7.8 km) |
Dam inundation, aircraft noise & air quality
annual average fine-particle (PM2.5) concentration across its census tracts is 7.0 μg/m³, and its composite pollution burden ranks around the 41th percentile statewide.
| Annual PM2.5 (tract average) | 7.0 μg/m³ |
| Pollution burden percentile (statewide) | ~41 |
Frequently asked questions
- Is Nicasio in a wildfire hazard severity zone?
- Per CAL FIRE's Fire Hazard Severity Zone maps, 3% is in a High zone, 97% is in a Moderate zone. The remainder of its area is outside currently designated zones.
- Is Nicasio in a FEMA flood zone?
- 6% of Nicasio lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO). Federally backed mortgages in a Special Flood Hazard Area generally require flood insurance.
- What earthquake faults and seismic zones affect Nicasio?
- The nearest mapped fault, the San Andreas fault zone, is about 4.9 mi (7.8 km) from the center of Nicasio.
- How do I check a specific address in Nicasio?
- Use the free sitelume interactive map at https://sitelume.com — search any Nicasio address to see which mapped zones it falls in, layer by layer.
Nearby in Marin County
Sources: CAL FIRE Fire Hazard Severity Zones; FEMA National Flood Hazard Layer; USGS Quaternary Faults; CGS Seismic Hazard Zones & Alquist-Priolo zones; Cal OES dam inundation maps; county ALUC noise contours; CalEnviroScreen 4.0. Area shares are computed against each place’s Census TIGER boundary (last computed 2026-07-24). Boundaries and zone designations change; always verify with the issuing agency.