Zoning Report
Cohasset, MA Zoning
Cohasset’s zoning bylaw is organized around several residential districts, village/harbor-oriented districts, an Open Space district, and a newer Section 3A compliance district labeled 3A-C. The source material clearly documents current dimensional rules, board authority, floodplain overlay rules, and some land alteration controls, but it does not include a full current use table or full parking article text. Recent amendments show the town has been actively updating its zoning, especially dimensional standards, floodplain rules, and related land-use provisions.
Last researched August 2026
Zoning Districts in Cohasset, MA
R-A
Lower-lot-size residential district allowing standard residential development subject to town dimensional controls.
Allowed uses: Residential uses not fully enumerated in provided sources, Two-family conversion and multifamily conversion are referenced in dimensional notes
R-B
Larger-lot residential district with lower intensity than R-A.
Allowed uses: Residential uses not fully enumerated in provided sources, Two-family conversion and multifamily conversion are referenced in dimensional notes
R-C
Largest-lot residential district in the materials provided, generally the lowest-density residential base district documented here.
Allowed uses: Residential uses not fully enumerated in provided sources, Two-family conversion and multifamily conversion are referenced in dimensional notes
HAR
Harbor-area district with urbanized dimensional standards and higher lot coverage than residential districts.
Allowed uses: Uses not fully enumerated in provided sources
VIL
Village district with compact dimensional standards intended for a built-up village setting.
Allowed uses: Uses not fully enumerated in provided sources
3A-C
District added for Section 3A/MBTA Communities compliance, with rules specifically accommodating dwellings containing two or more dwelling units and additional buffering requirements.
Allowed uses: Dwelling containing two or more dwelling units is expressly referenced in dimensional notes, Other uses not fully enumerated in provided sources
OS
Open Space district with low-intensity development expectations and strong clearing limits in the provided land alteration rules.
Allowed uses: Uses not fully enumerated in provided sources
Recent Zoning Changes
The sources show several recent adopted or advancing changes: a full dimensional rewrite approved in late 2023 and further amended in 2024; land alteration rules amended in 2024 and 2024 special town meeting; and floodplain overlay amendments advanced in 2025 to incorporate updated FEMA mapping. Cohasset also appears to have adopted a Section 3A compliance district (3A-C) by 2025, based on the current code table.
Setbacks, Lot Size & Height Limits in Cohasset, MA
Cohasset’s current dimensional framework is clearly documented in Article 5. Residential districts scale from R-A through R-C with increasingly larger lot requirements, while HAR and VIL are much more compact and 3A-C contains both base standards and separate standards for dwellings containing two or more dwelling units.
| District | Standard | Requirement |
|---|---|---|
| R-A | minimum lot area | 18,000 square feet — Plus "6,000 square feet" for each additional dwelling unit created in a two-family conversion or a multifamily conversion. |
| R-A | minimum lot frontage | 50 feet |
| R-A | minimum lot width | 100 feet |
| R-A | front setback | 20 feet — Except "10 feet" for any portion of a principal building with less than "15 feet" in height. |
| R-A | side setback | 15 feet — Accessory building exception to "3 feet" if less than "15 feet" in height and set back at least "75 feet" from the front lot line. |
| R-A | rear setback | 15 feet — Accessory building exception to "3 feet" if less than "15 feet" in height and set back at least "75 feet" from the front lot line. |
| R-A | maximum principal height | 35 feet |
| R-A | maximum accessory height | 25 feet — Except where bylaw otherwise limits certain accessory structures. |
| R-A | maximum total lot coverage | 30% |
| R-A | maximum building coverage | 20% — Except the lesser of "25% of the lot area" or "3,600 square feet" for a lawfully preexisting nonconforming lot containing less than "18,000 square feet". |
| R-B | minimum lot area | 35,000 square feet — "48,000 square feet" for a two-family conversion; "48,000 square feet for the first two dwelling units in a multifamily conversion plus 8,000 square feet for each additional dwelling unit." |
| R-B | minimum lot frontage | 50 feet |
| R-B | minimum lot width | 125 feet |
| R-B | front setback | 30 feet — Except "15 feet" for any portion of a principal building with less than "15 feet" in height. |
| R-B | side setback | 20 feet — Accessory building exception to "6 feet" if less than "15 feet" in height and set back at least "100 feet" from the front lot line. |
| R-B | rear setback | 20 feet — Accessory building exception to "6 feet" if less than "15 feet" in height and set back at least "100 feet" from the front lot line. |
| R-B | maximum principal height | 35 feet |
| R-B | maximum accessory height | 25 feet |
| R-B | maximum total lot coverage | 30% |
| R-B | maximum building coverage | 20% |
| R-C | minimum lot area | 60,000 square feet — "80,000 square feet" for a two-family conversion; "80,000 square feet for the first two dwelling units in a multifamily conversion plus 10,000 square feet for each additional dwelling unit." |
| R-C | minimum lot frontage | 50 feet |
| R-C | minimum lot width | 150 feet |
| R-C | front setback | 30 feet — Except "15 feet" for any portion of a principal building with less than "15 feet" in height. |
| R-C | side setback | 20 feet — Accessory building exception to "6 feet" if less than "15 feet" in height and set back at least "100 feet" from the front lot line. |
| R-C | rear setback | 30 feet — Accessory building exception to "6 feet" if less than "15 feet" in height and set back at least "100 feet" from the front lot line. |
| R-C | maximum principal height | 35 feet |
| R-C | maximum accessory height | 25 feet |
| R-C | maximum total lot coverage | 30% |
| R-C | maximum building coverage | 20% |
| HAR | minimum lot frontage | 20 feet |
| HAR | minimum lot width | 20 feet |
| HAR | front setback | 15 feet |
| HAR | side setback | 10 feet |
| HAR | rear setback | 15 feet |
| HAR | maximum principal height | 35 feet |
| HAR | maximum accessory height | 25 feet |
| HAR | maximum total lot coverage | 80% |
| VIL | minimum lot area | 5,000 square feet |
| VIL | minimum lot frontage | 50 feet |
Overlay Districts in Cohasset, MA
Floodplain and Watershed Protection Overlay District
Overlay district covering FEMA-mapped special flood hazard areas in Cohasset. It sits on top of the base zoning district, so both the base district rules and overlay rules apply.
Cohasset, MA Zoning FAQ
What are the setback requirements in Cohasset, MA?
Setbacks vary by district. Examples — R-A: 20 feet; R-A: 15 feet; R-A: 15 feet; R-B: 30 feet. Always confirm the exact yard requirements for your district with Cohasset, MA.
What is the minimum lot size in Cohasset, MA?
Minimum lot size depends on the zoning district — R-A: 18,000 square feet; R-A: 50 feet; R-A: 100 feet; R-B: 35,000 square feet.
How tall can buildings be in Cohasset, MA?
Height limits are set per district — R-A: 35 feet; R-A: 25 feet; R-B: 35 feet; R-B: 25 feet.
What zoning districts are in Cohasset, MA?
Cohasset, MA includes districts such as R-A, R-B, R-C, HAR, VIL, 3A-C, OS.
Are there flood zones or overlay districts in Cohasset, MA?
Environmental constraints are a significant zoning theme in Cohasset based on the supplied materials. The clearest constraints are the floodplain/watershed overlay, wetlands and stormwater cross-references, ledge-based topography, and lot coverage rules that discount certain constrained lands.
Have there been recent zoning changes in Cohasset, MA?
The sources show several recent adopted or advancing changes: a full dimensional rewrite approved in late 2023 and further amended in 2024; land alteration rules amended in 2024 and 2024 special town meeting; and floodplain overlay amendments advanced in 2025 to incorporate updated FEMA mapping.
Common questions about Cohasset, MA zoning
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Deal-fit, approval path & risk flags for Cohasset, MA
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- Table of Contents - Town of Cohasset, MA — Established that the eCode zoning bylaw includes legislation through 05-12-2025 and served as the baseline current code source.
- Article 5: Dimensional Regulations - Town of Cohasset, MA — Provided current dimensional table, district names, setbacks, lot sizes, coverage limits, and general measurement rules.
- 00206B40E94B240318151758 — Confirmed the 2023 special town meeting rewrite of Article 5 and helped corroborate dimensional standards.
- Article 9: Other Land Use Regulations - Town of Cohasset, MA — Provided current land alteration rules, purpose language about ledge-based topography, and special permit triggers for clearing and earth removal.
- Section 9.4 Floodplain & Watershed Protection Overlay District A. ... — Provided amendment language updating FEMA panels and the July 8, 2025 flood insurance study for the floodplain overlay.
- Article 12: Administration and Enforcement - Town of Cohasset, MA — Documented board powers, Building Inspector enforcement, appeal rights, Planning Board site plan review authority, and variance/special permit roles.
- AMENDMENTS TO ARTICLE 8 (NON-CONFORMING LOTS & ... — Provided nonconforming structure and use summary language and proposed Article 8 revisions, useful but needing verification against current adopted code.
- Agenda Center • Cohasset, MA • CivicEngage — Showed recent Planning Board meetings and specific public hearing items in 2026.
- Agenda Center • Cohasset, MA • CivicEngage — Confirmed ongoing board activity and recent posting dates for town boards.
- Zoning Board of Appeals March 4, 2025 - YouTube — Provided an example of active ZBA use variance review and practical context about board voting and self-storage discussion, though not used for hard zoning rules.
- Zoning for Flood Resilience: Helping Communities Weather the Storm — Provided context that MAPC worked with Cohasset on floodplain zoning updates in 2024; used only as secondary background, not for operative code text.
- Zoning Board of Appeals | Cohasset, MA — Confirmed existence of the ZBA as an active municipal board page.
This summary is AI-generated from public municipal sources and is not legal, engineering, or land-use advice. Always verify zoning with Cohasset, MA officials before making decisions.