Can you build a duplex in Cohasset, MA?
The current code clearly contemplates dwellings containing two or more dwelling units in the 3A-C district and references multifamily conversion standards in residential districts. But the missing use table prevents a confident by-right conclusion.
Confidence: medium · Last researched August 2026
Dimensional standards in Cohasset, MA
| R-A — minimum lot area | 18,000 square feet |
| R-A — front setback | 20 feet |
| R-A — side setback | 15 feet |
| R-A — rear setback | 15 feet |
| R-B — minimum lot area | 35,000 square feet |
| R-B — front setback | 30 feet |
| R-B — side setback | 20 feet |
| R-B — rear setback | 20 feet |
| R-C — minimum lot area | 60,000 square feet |
| R-C — front setback | 30 feet |
| R-C — side setback | 20 feet |
| R-C — rear setback | 30 feet |
| HAR — front setback | 15 feet |
| HAR — side setback | 10 feet |
| HAR — rear setback | 15 feet |
| VIL — minimum lot area | 5,000 square feet |
| VIL — front setback | 15 feet |
| VIL — side setback | 10 feet |
| VIL — rear setback | 15 feet |
| 3A-C — minimum lot area | 10,000 square feet |
| 3A-C — front setback | 50 feet |
| 3A-C — side setback | 20 feet |
| 3A-C — rear setback | 20 feet |
| OS — front setback | 30 feet |
| OS — side setback | 20 feet |
| OS — rear setback | 30 feet |
| All districts — lot area calculation rule | May not include any land within the limits of an abutting street or private way, or any portion of the lot below mean high water |
| All districts — front setback measurement rule on narrow rights-of-way | Where a street has a right-of-way width of less than 40 feet, the setback distance shall include an additional 20 feet and be measured from the center line of the street |
Related questions
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.
Full investor analysis
The full Cohasset, MA report breaks down duplex and 2–4 unit feasibility by district, the approval path, and the density/dimensional limits that decide whether the numbers work. First town report is free.
Get the full Cohasset, MA report free →More about Cohasset, MA zoning
- Can you build an ADU in Cohasset, MA?→
- Are short-term rentals allowed in Cohasset, MA?→
- Is mixed-use development allowed in Cohasset, MA?→
- What are the setback requirements in Cohasset, MA?→
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.
More Massachusetts zoning reports →