Marin County, California GIS Map
This GIS map of Marin County, California (CA) shows the official Census county boundary (FIPS 06041), with federal layers you can switch on for FEMA flood zones, USGS elevation contours and hillshade, NLCD land cover, and school district lines.
Marin County has a population of about 257,969 (U.S. Census Bureau, 2020-2024 ACS 5-year estimate) and a land area of 520.1 square miles. Use the inspect tool to read coordinates, elevation and the layers under any point.
- State
- California (CA)
- Population
- 257,969
- Land area
- 520.1 sq mi
- Density
- 496 / sq mi
- Coordinates
- 38.0514, -122.7464
- FIPS code
- 06041
Marin County Demographics
Source: U.S. Census Bureau, American Community Survey 2020-2024 5-year estimates.
Population
257,969
Households
103,018
Median household income
$149,091
Median age
47.4 years
Median home value
$1,507,300
Median gross rent
$2,668/mo
Owner-occupied homes
64.7%
Bachelor's degree or higher
61.1%
Below poverty level
8.3%
Land area
520.1 sq mi
Population density
496 / sq mi
Marin County Population Growth
Source: U.S. Census Bureau, 2010 Census and Population Estimates Program (Vintage 2024: April 2020 estimates base and July 1, 2024 estimate).
2010 Census
252,409
April 2020 (estimates base)
262,325
July 2024 estimate
256,400
Change 2010-2020
+3.9%
Change 2020-2024
-2.3%
Natural Hazard Risk in Marin County
FEMA National Risk Index ratings for Marin County, compared with all U.S. counties.
Overall risk
Score 96.4 of 100
Expected annual loss
Buildings, population & agriculture
Social vulnerability
Susceptibility to hazard impacts
Community resilience
Ability to prepare & recover
Risk by Hazard
- LandslideRelatively High
- EarthquakeRelatively High
- Coastal FloodingVery High
- Inland FloodingRelatively High
- WildfireRelatively Moderate
- Heat WaveRelatively Low
- TsunamiRelatively Moderate
- Volcanic ActivityVery Low
- DroughtRelatively Low
- LightningRelatively Low
- TornadoVery Low
- Strong WindVery Low
- Winter WeatherVery Low
- HailVery Low
Source: FEMA National Risk Index (December 2025 release). County-level ratings are relative to other U.S. counties and are not a property-specific assessment.
Environmental Conditions in Marin County, California
Radon potential, monitored air quality and current drought status for Marin County, California, from the Environmental Protection Agency and the U.S. Drought Monitor.
Radon potential
Zone 3
low radon potential
EPA predicts an average indoor level below 2 pCi/L, so the EPA still recommends testing, because elevated radon can occur anywhere.
Air quality (2024)
Median AQI 28Good
No days reached unhealthy levels.
90th percentile 52, peak 86 across 357 monitored days.
Drought status
No drought
Drought Severity and Coverage Index 0 of 500.
Map of 13 October 2026.
Sources: EPA Map of Radon Zones (September 2025), EPA Air Quality Index (2024) and the U.S. Drought Monitor. A radon zone is a regional planning tool, not a prediction for any individual home — the EPA recommends testing every home regardless of zone. Air quality is shown only for counties that host an EPA monitor. Drought figures describe one weekly map, not a long-term climate average. Compare counties in California.
GIS Data for Marin County, CA
The Marin County GIS map on this page loads live federal layers in your browser, so you can check flood zones, terrain, land cover and district boundaries anywhere in Marin County without a separate GIS login. All of the Marin GIS data below is drawn from public U.S. government sources.
Layers you can turn on
FEMA flood zones
National Flood Hazard Layer — flood insurance rate map zones and floodways.
Elevation contours and hillshade
USGS 3DEP terrain, so you can read slope and relief across the county.
Land cover
NLCD land cover classes — forest, developed, wetland and water.
School districts
Census TIGER unified and elementary school district boundaries.
ZIP code and county boundaries
Census TIGER ZCTA and county boundary lines.
Map tools
Measure distance and area
Draw a line or polygon to get length in miles or area in acres.
Sketch and annotate
Add points, lines and shapes on top of the map.
Inspect any point
Click the map to read coordinates, elevation and the layers under your cursor.
Download the map
Save the current view as a PNG image.
Where the data comes from
County boundaries come from the U.S. Census Bureau TIGER/Line program, flood zones from FEMA's National Flood Hazard Layer, terrain from the USGS 3D Elevation Program, land cover from the Multi-Resolution Land Characteristics Consortium, and demographics from the American Community Survey.
Property records and tax maps in Marin County
Most people who look up Marin County GIS data are after parcel-level records: who owns a property, what it last sold for, and what it is assessed at. Those records are kept locally, not federally, so they are not part of this map. Marin County property and tax map data lives with the county's own records office, and what that office is called varies by state — Texas counties run an appraisal district (usually searched as a “CAD”), Kentucky uses a Property Valuation Administrator (PVA), and most other states use a county assessor, auditor or tax office. Start with that office for a deed, a tax map number or a parcel boundary; use the map above for flood zones, elevation and land cover on the same land.
Marin County FAQ
What state is Marin County in?
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Marin County is a county in California (CA).
What is the population of Marin County?
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Marin County, California has a population of about 257,969, according to the U.S. Census Bureau American Community Survey.
How big is Marin County?
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Marin County covers about 520.1 square miles of land, with a population density of roughly 496 people per square mile.
What is the FIPS code for Marin County?
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The FIPS county code for Marin County, California is 06041. It is used to identify the county in federal datasets such as Census TIGER and FEMA flood maps.
What is the median household income in Marin County?
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The median household income in Marin County, California is about $149,091 per year.
What is the radon zone for Marin County?
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Marin County is in EPA radon Zone 3, meaning the EPA predicts an average indoor radon level below 2 pCi/L. In this zone the EPA still recommends testing, because elevated radon can occur anywhere. The EPA is clear that a radon zone is a regional planning tool and not a prediction for any individual home.
What is the air quality in Marin County?
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Across 2024, the EPA monitor covering Marin County recorded a median Air Quality Index of 28 (Good) and a 90th percentile of 52, with a peak of 86. No days reached the unhealthy for sensitive groups category. Only counties that host an EPA monitor have these figures.
Is Marin County in a drought?
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As of the 13 October 2026 U.S. Drought Monitor map, no part of Marin County is in drought.
What is Marin GIS?
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Marin GIS usually refers to the county's own parcel and zoning mapping system, which Marin County publishes itself. This page is a separate, free viewer: it draws federal GIS layers — FEMA flood zones, USGS elevation, NLCD land cover and Census boundaries — over the Marin County boundary, with no login required.
What GIS data is available for Marin County?
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The Marin County map loads federal GIS layers directly in your browser: FEMA National Flood Hazard Layer flood zones, USGS 3DEP elevation contours and hillshade, NLCD land cover, Census TIGER school district boundaries, and TIGER ZIP code and county boundary lines.
How do I check flood zones in Marin County?
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Open the Marin County map, turn on the FEMA flood zones layer, and zoom in. The National Flood Hazard Layer shows flood insurance rate map zones and floodways. Flood zones only draw once you are zoomed in far enough.
How do I find the coordinates or elevation of a spot in Marin County?
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Use the inspect tool on the Marin County map and click any point. It reads back the coordinates, elevation and the layers under your cursor. You can also measure distance and area by drawing a line or polygon.
Data sources for Marin County, California
Every figure on this page comes from a published government dataset. Each source is listed with its release date so you can check the number or cite it directly.
- American Community Survey 5-year estimates
U.S. Census Bureau · 2020-2024 · population, income, housing, education and poverty figures
- Gazetteer Files
U.S. Census Bureau · 2024 · place coordinates, land area and the county/place/ZIP crosswalk
- TIGER/Line Shapefiles
U.S. Census Bureau · 2024 · county, ZIP Code Tabulation Area and school district boundaries
- National Flood Hazard Layer
Federal Emergency Management Agency · current effective Flood Insurance Rate Maps · flood zones, floodways and base flood elevations
- National Risk Index
Federal Emergency Management Agency · v1.20, December 2025 · county natural hazard risk, expected annual loss, social vulnerability and resilience
- 3D Elevation Program (3DEP)
U.S. Geological Survey · current · elevation contours, shaded relief and point elevations
- National Land Cover Database
Multi-Resolution Land Characteristics Consortium · NLCD 2021 · land cover classes such as developed, forest, crop and water
- Map of Radon Zones
U.S. Environmental Protection Agency · September 2025 · the county radon zone (1, 2 or 3) and its predicted indoor radon potential
- Air Quality Index annual summary by county
U.S. Environmental Protection Agency · 2024 · median, 90th percentile and peak AQI, and days at unhealthy levels, for counties with an EPA monitor
- U.S. Drought Monitor
National Drought Mitigation Center, USDA and NOAA · weekly, current map · the share of county area in each drought category and the Drought Severity and Coverage Index
- ArcGIS basemaps
Esri · current · streets, satellite, topographic and dark gray basemap tiles
Citing this page
GIS Map, “Marin County, California GIS Map”, https://gismap.land/county/california/marin. Figures from the datasets listed above.
Local notes for Marin County, CA
Questions and local knowledge from people who know the area. Every note is read before it appears here.