Marin County Unincorporated, California Zoning Map
Zoning, overlays and hazards on every parcel — and an answer to what the code actually lets you build. Compiled from current zoning data for all 334 districts.
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What's in the Marin County Unincorporated dataset
Every field below is available for any Marin County Unincorporated parcel, on the map and through the AI.
Zoning
- District code & full name
- Parcel boundary & APN
- All 334 districts mapped
Building controls
- Maximum building height
- Floor area ratio (FAR)
- Front setback
- Side setback
Overlays, hazards & AI
- Flood hazard & environmental layers
- Ask the AI about any parcel
- Powered by live parcel data
Where uses are permitted in Marin County Unincorporated
Share of Marin County Unincorporated's zoned land where each use is permitted.
- Single-family
- 88.04%
- Multi-family
- 39.68%
- ADU
- 87.81%
- Two-family
- 27.77%
- Retail
- 99.70%
- Eating & drinking
- 0.53%
- Office
- 6.36%
- Hotel / motel
- 2.13%
- Industrial
- 32.84%
- Storage & warehouses
- 55.16%
Marin County Unincorporated, California Zoning Districts: What Do They Mean?
Zoning districts are areas regulated by specific laws that determine land use, building types, and development rules. Each district below shows its zone type and which uses it permits.
| Zone Code | Category | Area | Details |
|---|---|---|---|
A10 Agriculture And Conservation | - | 165.6 ac | Standards & uses → |
A2 Agriculture Limited | - | 28,022 ac | Standards & uses → |
A20 Agriculture And Conservation | - | 382.8 ac | Standards & uses → |
A2-B1 Agriculture Limited Minimum Lot Size Combining District | - | 20.9 ac | Standards & uses → |
Showing 4 of 334 districts
Start from what you're trying to build
Each one runs against the live Marin County Unincorporated dataset and returns the districts, standards and approvals involved.
What should developers know about Marin County Unincorporated zoning?
Unincorporated Marin County is, in zoning terms, overwhelmingly rural and agricultural. The mapped land is dominated by large-lot agriculture and conservation districts - the A60 (Agriculture and Conservation) district alone spans more than 70,000 acres, with A40 and A2 (Agriculture Limited) adding tens of thousands more. This is a landscape engineered to keep parcels large and development sparse, reinforced by minimum-lot-size combining districts (the -B suffixes such as A2-B4 and A2-B2) that dictate how much land a single dwelling requires. For developers and investors, the headline is that Marin's unincorporated areas are among the most development-constrained in California, by design.
Where residential capacity exists, it is largely channeled through the Agriculture Residential Planned (ARP) family - ARP-2, ARP-10, ARP-20 and their variants - which pairs planned-residential standards with agricultural and conservation objectives. Several districts now carry a Housing Overlay Designation (the -HOD suffix, as in A2-HOD, A60-HOD and AP-HOD), reflecting state-driven pressure to identify sites for additional housing within a county that has historically resisted density. Other combining layers tie zoning to place: Bayfront Conservation (-BFC) and San Geronimo Valley (-SGV) suffixes attach location-specific protections.
With 334 mapped zoning designations - of which the dataset surfaces the 30 largest - the county's code is unusually granular, stacking base agricultural districts with combining and overlay layers. Building controls include FAR, lot, multi-unit, density, coverage, pervious-surface, lot-width, height and full setback standards. The practical reality is that most parcels are governed by a stack of designations at once, so feasibility turns on decoding the full combining-district string, not just the base zone. This is pre-development intelligence, not legal advice - verify with the local planning department before acquisition.
Marin County Unincorporated zoning: frequently asked questions
Why is so much of unincorporated Marin zoned agricultural?
The county's mapped land is dominated by large-lot agriculture and conservation districts - A60 alone exceeds 70,000 acres, with A40 and A2 (Agriculture Limited) adding substantial area. These districts are intended to preserve open ranch and farm land and keep development sparse, which is why unincorporated Marin is among the most building-constrained jurisdictions in the state.
What do the -B suffix combining districts (like A2-B4) control?
The -B designations are minimum-lot-size combining districts layered onto a base agricultural zone. They set how much land is required per dwelling, effectively governing how finely a parcel can be divided. Because they ride on top of districts like A2, you cannot assess development potential from the base zone alone - you must read the full combining string.
What is the Housing Overlay Designation (HOD) and where does it apply?
The -HOD suffix marks parcels carrying a Housing Overlay Designation, seen on districts such as A2-HOD, A60-HOD, AP-HOD and ARP-2-HOD. It reflects the county's response to California housing-element obligations by identifying sites where additional housing is contemplated. These overlays are the most likely places to find incremental residential capacity in an otherwise restrictive map.
Where can planned residential development actually occur?
Residential capacity is concentrated in the Agriculture Residential Planned (ARP) family - ARP-1 through ARP-20 and their variants - which blends planned-residential standards with agricultural and conservation goals. Even here, location-specific combining layers like Bayfront Conservation (-BFC) and San Geronimo Valley (-SGV) attach further constraints that shape what is buildable.
How should a developer approach Marin's layered zoning code?
Treat the full designation string as the unit of analysis. With 334 distinct mapped designations, most parcels carry a base agricultural district plus one or more combining and overlay layers - minimum-lot-size (-B), housing overlay (-HOD), and place-based protections (-BFC, -SGV). Feasibility, division potential and permitted density all depend on decoding that complete stack rather than the base zone in isolation.
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Zoning data is pre-development intelligence, not legal advice. Verify with the Marin County Unincorporated planning department before acquisition or design.