Trinity County — Zoning

Last reviewed: July 6, 2026

Overview

Trinity County’s zoning rules apply to the unincorporated areas and are codified in Title 17 of the Trinity County Code of Ordinances (the “Zoning Ordinance”). The ordinance creates named zoning districts, overlay/combining areas, and countywide standards that govern what uses are allowed and where buildings can go. District boundaries are shown on official sectional zoning maps; any unincorporated land not shown on those maps defaults to the Unclassified district until rezoned. See § 17.04.010, § 17.05.010, § 17.07.010, § 17.08.010 and § 17.09.010 .

In unincorporated Trinity County, if your parcel isn’t shown on the official sectional zoning maps, it defaults to the U (Unclassified) district until the County reclassifies it through a zoning action (§ 17.05.010; § 17.07.010) .

For a broader context on how zoning fits into permits and site planning, see the Trinity County zoning & planning overview, and cross-reference related topics: Land Use, Development Standards, Parking, Design Review, Overlay Districts, Nonconforming Uses, Variances and Exceptions, and Signage. State-level topics like the California Building Standards Code and California ADU law are separate from local zoning.

Districts at a glance

Title 17 establishes the following districts: U, A, RD‑I/II, A‑F, R‑R, R‑1, R‑2, R‑3, C‑N, C‑1, C‑2, H‑C, M, SUD, SC, OS, M‑H, TPZ, PF, MI (§ 17.04.010) .

Below is a district‑by‑district summary for unincorporated Trinity County. Where the ordinance content was not retrieved, this page notes “Not found in retrieved materials.”

U — Unclassified

• Purpose: Default zoning for unincorporated land not shown on the sectional maps (§ 17.07.010) .
• Typical permitted uses: Not found in retrieved materials.
• Key dimensional standards: Not found in retrieved materials.
• Where it applies: Any unincorporated parcel not designated on the zoning maps until rezoned (§ 17.05.010; § 17.08.010; § 17.09.010) .

A — Agricultural

• Purpose: Agricultural production and rural living (§ 17.13.005) .
• Typical permitted uses: Broad agricultural uses and one single‑family dwelling; feedyards, poultry/hog raising, and agricultural processing require a use permit (§ 17.13.010, § 17.13.020) .
• Key dimensional standards: Min. lot width 100 ft; max. height 40 ft; front 20 ft; side 20 ft; rear 20 ft; no max lot coverage (§ 17.13.060–.110) .
• Where it applies: Agricultural areas of unincorporated county (§ 17.13.005) .

AP — Agricultural Preserve (Williamson Act)

• Purpose: Preserve large agricultural lands under Land Conservation Act contracts (§ 17.13A.010) .
• Typical permitted uses: Animal husbandry, orchards, vineyards, dairies; farm labor quarters, hydroelectric for commercial use, and similar intensive activities require a use permit (§ 17.13A.020–.030) .
• Key dimensional standards: Not found in retrieved materials (chapter continues at § 17.13A.050 for minimum parcel area).
• Where it applies: Contracted preserve lands of at least 100 acres (§ 17.13A.010) .

AF — Agriculture–Forest

• Purpose: Mixed agriculture and timberland management (§ 17.14.040–.110; summary) .
• Typical permitted uses: Growing/harvesting timber, agriculture, one single‑family dwelling; resorts, RV parks, sawmills by use permit (§ 17.14.040; § 17.14.050; uses list continues) .
• Key dimensional standards: Subdivision minimums: 10 acres (Site IV/V) or 40 acres (Site I–III) (§ 17.14.050) ; max height 40 ft (§ 17.14.060) ; yards 20 ft, but 100 ft where abutting TPZ (§ 17.14.070–.090) ; waterbody setback 200 ft or per Forest Practice Act (§ 17.14.100) .
• Where it applies: Forested rural areas; some cannabis activities are also keyed to AF zoning by separate chapters (see references below).

RR — Rural Residential

• Purpose: Low‑density rural living (§ 17.15.005) .
• Typical permitted uses: Single‑family dwelling and limited agriculture with animal density caps; more intensive livestock operations and campgrounds require a use permit (§ 17.15.010–.020) .
• Key dimensional standards: Not fully consolidated in one place in retrieved text; one chapter shows a common RR standard set with 5‑acre minimum lot area, 100‑ft minimum width, 40‑ft max height, and 20‑ft front/20‑ft rear/10‑ft side yard minimums (§ 17.11.040–.100) — verify these against current parcel zoning suffixes (e.g., RR‑5) (§ 17.11.040–.100) .
• Where it applies: Rural neighborhoods outside communities.

R‑1 — One‑Family Residence

• Purpose, uses, standards: Not found in retrieved materials (listed in § 17.04.010) . Verify with the jurisdiction.

R‑2 — Duplex Residence

• Purpose, uses, standards: Not found in retrieved materials (listed in § 17.04.010) . Verify with the jurisdiction.

R‑3 — Multiple Family

• Purpose: Provide multifamily sites where services exist (§ 17.18.010) .
• Typical permitted uses: Duplexes, triplexes, apartments, condos; single‑family and certain institutional/office uses by use permit (§ 17.18.020–.030) .
• Key dimensional standards: Min lot 16,000 sf (§ 17.18.040); min width 75 ft (§ 17.18.050); max height 25 ft (45 ft in Weaverville FPD) (§ 17.18.060) ; front 20 ft (§ 17.18.070), interior side 10 ft/exterior side 15 ft (§ 17.18.080), rear 15 ft (§ 17.18.090); max lot coverage 40% (§ 17.18.100); min lot area per unit 2,000 sf (§ 17.18.130) .
• Where it applies: Higher‑density residential areas in unincorporated communities.

R‑O — Residential–Office

• Purpose: Mixed low‑intensity office/residential alternative to commercial zoning (§ 17.18A.010) .
• Typical permitted uses: Single‑family dwelling and small day care; professional offices and improved parking by use permit (§ 17.18A.020–.030) .
• Key dimensional standards: For subdivisions, min lot 7,000 sf (§ 17.18A.070) . Other baseline yards reference general standards; see Development Standards.
• Where it applies: Select mixed‑use corridors.

C‑N — Neighborhood Commercial

• Purpose, uses, standards: Not found in retrieved materials (listed in § 17.04.010) . Verify with the jurisdiction.

C‑1 — Retail Business

• Purpose, uses, standards: Not found in retrieved materials (listed in § 17.04.010) . Verify with the jurisdiction.

C‑2 — General Commercial

• Purpose/uses: Not comprehensively retrieved. Note: Certain cannabis distribution, manufacturing (nonvolatile/mechanical), and processing uses are allowed in C‑2 subject to permits (§ 17.43B.020; § 17.43F.020; § 17.43I.020) .
• Key dimensional standards: Not found in retrieved materials. Verify with the jurisdiction.

C‑3 — Heavy Commercial

• Purpose/uses: Not listed in § 17.04.010 but referenced throughout cannabis chapters as “Heavy Commercial (C‑3)” with allowances for distribution, manufacturing, and processing by permit (§ 17.43B.020; § 17.43F.020; § 17.43I.020) .
• Key dimensional standards: Not found in retrieved materials. Verify with the jurisdiction.

H‑C — Highway Commercial

• Purpose, uses, standards: Not found in retrieved materials (listed in § 17.04.010) . Verify with the jurisdiction.

M / I — Industrial

• Purpose/uses: § 17.04.010 lists “M Industrial,” while later chapters reference “I Industrial” for cannabis. Industrial uses for cannabis are permitted in “I” zones by specific permits (§ 17.43B.020; § 17.43F.020; § 17.43I.020) .
• Key dimensional standards: Not found in retrieved materials. Verify whether Trinity County currently uses “M” or “I,” or both.

SUD — Specific Unit Development

• Purpose: Site‑specific zoning governed by adopted SUD guidelines. Several cannabis uses are allowed only where SUD guidelines identify parcels for industrial development (§ 17.43B.020; § 17.43F.020; § 17.43I.020) .
• Uses/standards: Not found broadly in retrieved materials; check parcel‑specific SUD documents.

SC — Scenic Conservation (Overlay)

• Purpose: Protect scenic resources with project‑level review in mapped overlay areas (§ 17.25.030–.050) .
• Uses: Underlying zoning uses remain; certain activities (buildings, roads/driveways, decks, wells, vegetation removal using machinery) require a Planning Director use permit within the SC overlay portion of a parcel (§ 17.25.030–.040) .
• Key standards: Scope limited to siting and specific improvements; exceptions exist where prior CEQA/THP review covered the work (§ 17.25.050) .

OS — Open Space

• Purpose: Protect significant habitat and areas unsuitable for development (§ 17.25A.010) .
• Uses: Land/forest management, habitat enhancement, grazing; low‑intensity recreation and mining require a use permit (§ 17.25A.020–.030) .
• Key dimensional standards: Not found in retrieved materials.

M‑H — Mobile Home

• Purpose, uses, standards: Not found in retrieved materials (listed in § 17.04.010) . Verify with the jurisdiction.

TPZ — Timberland Production

• Purpose: Long‑term timberland zoning with compatible uses (§ 17.14A.010–.030) .
• Typical permitted uses: Timber growing/harvesting, watershed/wildlife management; one single‑family dwelling and certain timber facilities allowed by use permit (§ 17.14A.020–.030) .
• Key dimensional standards: If not specified for a TPZ district, min. division size is 160 acres (§ 17.14A.040) ; min lot width 400 ft (§ 17.14A.060); all yards 50 ft (100 ft from other TPZ or federal lands) (§ 17.14A.070); siting compatibility with Timber Management/Harvest Plan required (§ 17.14A.080) .
• Where it applies: Mapped TPZ lands; entry standards tied to timber site classes and a Timber Management Plan (§ 17.14A.050) .

PF — Public Facilities

• Purpose: Governmental, utility, educational and other public‑interest facilities (§ 17.29.010) .
• Typical permitted uses: Government offices, small parks, playgrounds, libraries, post offices; larger or more intensive facilities (airports, hospitals, schools, jails, utilities, yards) require a use permit (§ 17.29.020–.030) .
• Key dimensional standards: Not found in retrieved materials.

MI — Mining

• Purpose, uses, standards: Not found in retrieved materials (listed in § 17.04.010) . Verify with the jurisdiction.

RD‑1 and RD‑2 — Recreation Development

• Purpose: RD‑1 implements regulations within the Whiskeytown‑Shasta‑Trinity National Recreation Area to allow compatible private use and protect “improved property” (§ 17.26.008) .
• Uses/standards: Not fully retrieved; see § 17.26.005–.010 for applicability and permitted uses (RD‑2 not retrieved) .

Overlay and Combining Districts

• FH — Flood Hazard: Applies to mapped FEMA floodways/AE zones, certain Zone A areas, and locally identified 100‑year floodplains; allows limited uses by right and others by floodplain development permit (§ 17.29B.050–.070) .
• B‑1/B‑2/B‑3 — Special Building Site Areas (combining): Replace underlying minimum lot size/width with 10,000 sf/100 ft (B‑1), 15,000 sf/100 ft (B‑2), or as specified on zoning map (B‑3) (§ 17.28.010) .
• SC — Scenic Conservation: See above.

Countywide development rules that cut across districts

• Building/yard location: Where official building lines are shown or an official highway building line applies, measure yards from those lines; countywide 50‑ft building setback from the centerline of state highways and Federal‑aid secondary roads (§ 17.30.060(C)) .
• Architectural projections: Eaves/canopies may encroach up to 30 inches into required yards (§ 17.30.060(D)) .
• Accessory buildings: Attached accessory buildings match main building setbacks; detached accessory buildings have minimum driveway length and baseline setbacks by zone class; max height 25 ft unless a use permit allows more (§ 17.30D.030–.040) .
• Applications/hearings: Entitlements use the standard filing, completeness, hearing, and appeal procedures (§ 17.30E.010–.020; § 17.34.010–.060) .

Selected district standards (quick reference)

For parking ratios, landscaping, and any design‑review triggers that may accompany these districts, see Parking, Landscaping and Screening, and Design Review.

Use‑specific notes: commercial cannabis siting

Trinity County regulates commercial cannabis activities by license type and zoning district. For example:

• Distribution (Type 11) may be allowed in C‑2, C‑3, I, A, SUD, AF with a conditional use permit (§ 17.43B.020) .
• Manufacturing (Type 6/N/P nonvolatile/mechanical) may be allowed in C‑2, C‑3, I, A, SUD, AP, AF; microbusiness manufacturing may be allowed in RR and U by permit; volatile (Type 7) limited to C‑3, I, SUD with CUP (§ 17.43F.020) .
• Processing may be allowed in C‑2, C‑3 (CUP), or I, A, SUD, AP, AF (Director’s use permit) (§ 17.43I.020) .

Geographic “opt‑out” areas and recreation areas are excluded for several cannabis licenses; confirm site eligibility early (§ 17.43F.020; § 17.43I.020) .

Checklist

• Confirm your base zoning and any suffixes/combining/overlay designations on the official zoning maps for unincorporated areas (§ 17.05.010; § 17.08.010; § 17.09.010) .
• Identify overlays: SC, FH, and any B‑1/B‑2/B‑3 combining zone on the parcel (§ 17.25.030–.050; § 17.29B.050–.070; § 17.28.010) .
• Check district‑specific dimensional standards (setbacks, height, lot size) in your zone (e.g., A, AF, R‑3, TPZ) and the countywide highway setback rule (§ 17.13.060–.110; § 17.14.050–.100; § 17.18.040–.100; § 17.14A.060–.070; § 17.30.060(C)) .
• Verify allowed use and permit type (by‑right vs use permit). For cannabis, match license type to zoning and note excluded areas (§ 17.43B.020; § 17.43F.020; § 17.43I.020) .
• Confirm Parking, Design Review, and any Variances and Exceptions process needs before filing.
• If near waterbodies or within FH overlay, check special setbacks/permits (§ 17.14.100; § 17.29B.070) .
• If using accessory buildings, apply the county’s accessory standards and verify setbacks by zone (§ 17.30D.030–.040) .

Risks & Ambiguities

Plain-English Summary

In unincorporated Trinity County, each parcel carries a mapped zoning district that controls what you can build and how far it must sit from roads, water, and property lines. Start by confirming your zoning and any overlays on the County’s sectional maps, then match your proposed use to the district’s allowed uses and dimensional rules; special overlays like Scenic Conservation or Flood Hazard can add director‑level or floodplain permits on top of your base zoning.

Information Gaps

• Full text for R‑1, R‑2, C‑N, C‑1, H‑C, M‑H, MI districts: Not found in retrieved materials.
• Base dimensional standards for C‑2/C‑3/I and PF districts: Not found in retrieved materials.
• RD‑2 district details: Not found in retrieved materials.

Source References

• Title 17 structure, purpose, and nature of zoning; district roster; zoning maps (§ 17.02.010; § 17.03.010; § 17.04.010; § 17.05.010; § 17.08.010; § 17.09.010) .
• Effect of districts; Unclassified district (§ 17.06.010; § 17.07.010) .
• A district uses and standards (§ 17.13.005–.110) .
• AP district description and uses (§ 17.13A.010–.040) .
• AF district permitted uses and standards (§ 17.14.040–.110) .
• RR district uses (§ 17.15.005–.020) and related dimensional set shown at (§ 17.11.040–.100) .
• R‑3 and R‑O districts (§ 17.18.010–.150; § 17.18A.010–.080) .
• PF district uses (§ 17.29.010–.030) .
• TPZ district and standards (§ 17.14A.010–.090) .
• SC overlay and OS district (§ 17.25.030–.050; § 17.25A.010–.030) .
• Flood Hazard overlay (§ 17.29B.050–.070) .
• Special Building Site Areas B‑1/B‑2/B‑3 (§ 17.28.010) .
• Countywide yard/location rules (§ 17.30.060) and accessory building standards (§ 17.30D.030–.040) .
• Cannabis siting by district (§ 17.43B.020; § 17.43F.020; § 17.43I.020) .

Retrieved passages

• Trinity County Zoning Code (Title 17) High relevance show source text
• Trinity County Zoning Code (§ 1) High relevance show source text
• Trinity County Zoning Code (Chapter 17.32) High relevance show source text
• Trinity County Zoning Code (Chapter 17.32) High relevance show source text
• Trinity County Zoning Code (§ 2) High relevance show source text
• Trinity County Zoning Code (Section 17.43F.040) High relevance show source text
• Trinity County Zoning Code (Chapter 17.02) High relevance show source text
• Trinity County Zoning Code (§ 3) High relevance show source text
• Trinity County Zoning Code (section 31) High relevance show source text
• Trinity County Zoning Code (§ 1) High relevance show source text
• Trinity County Zoning Code (Article 1) High relevance show source text
• Trinity County Zoning Code (Section 17.30.060.) Medium relevance show source text
• Trinity County Zoning Code (Section 17.30C.020.) Medium relevance show source text
• Trinity County Zoning Code (§ I) Medium relevance show source text
• Trinity County Zoning Code (Section 17.30.060.) Medium relevance show source text
• Trinity County Zoning Code (Section 17.30.010) Medium relevance show source text

Cited sections

• Title 17 structure, purpose, and nature of zoning; district roster; zoning maps (§ 17.02.010; § 17.03.010; § 17.04.010; § 17.05.010; § 17.08.010; § 17.09.010) . (Title 17)
• Effect of districts; Unclassified district (§ 17.06.010; § 17.07.010) . (§ 17.06.010)
• A district uses and standards (§ 17.13.005–.110) . (§ 17.13.005)
• AP district description and uses (§ 17.13A.010–.040) . (§ 17.13A.010)
• AF district permitted uses and standards (§ 17.14.040–.110) . (§ 17.14.040)
• RR district uses (§ 17.15.005–.020) and related dimensional set shown at (§ 17.11.040–.100) . (§ 17.15.005)
• R‑3 and R‑O districts (§ 17.18.010–.150; § 17.18A.010–.080) . (§ 17.18.010)
• PF district uses (§ 17.29.010–.030) . (§ 17.29.010)
• TPZ district and standards (§ 17.14A.010–.090) . (§ 17.14A.010)
• SC overlay and OS district (§ 17.25.030–.050; § 17.25A.010–.030) . (§ 17.25.030)
• Flood Hazard overlay (§ 17.29B.050–.070) . (§ 17.29B.050)
• Special Building Site Areas B‑1/B‑2/B‑3 (§ 17.28.010) . (§ 17.28.010)
• Countywide yard/location rules (§ 17.30.060) and accessory building standards (§ 17.30D.030–.040) . (§ 17.30.060)
• Cannabis siting by district (§ 17.43B.020; § 17.43F.020; § 17.43I.020) . (§ 17.43B.020)
• TrinityCounty_ZoningCode.md

• Official Trinity County code library