What does R-6 zoning mean in Portland, Maine?

R-6 is Portland's highest-density residential district, permitting multi-story apartment buildings at the smallest minimum lot area per unit in the code. It's concentrated in and around the peninsula's dense historic neighborhoods.

How do I find the zoning for an address in Portland, Maine?

Use the city's online zoning/GIS viewer, which returns the base district and any overlays (shoreland, historic, flood) for a given parcel. The Planning and Urban Development office can confirm interpretations for unusual lots.

Can I build an ADU in Portland, Maine?

Yes. Portland allows accessory dwelling units broadly following Maine's 2022 statewide ADU law, and the city eliminated many parking minimums for these units as part of a 2023 council vote — check current district-specific limits before designing.

Portland, Maine · city zoning districts · 15 districts

Portland, ME zoning map & districts

Portland's zoning is codified in the Land Use Code (Title 14 of the City Code), administered by the Department of Planning and Urban Development / Permitting and Inspections. The city underwent "ReCode Portland," its first comprehensive rewrite of the land use code in over 50 years, which consolidated legacy districts and simplified permitted-use tables citywide. Residential density steps up sharply toward the peninsula, where the highest-density R-6 districts and the B-3 downtown business district allow multi-story mixed-use buildings with minimal parking; outer neighborhoods remain lower-density R-1 and R-2.

The code Portland Land Use Code

Portland zoning map

The City's online GIS mapping application (Portland Maine Property/Zoning Viewer) shows parcel-level zoning; the Land Use Code text is maintained by the Department of Planning and Urban Development and posted on the city's website.

There is no link to the official map here yet — confirm current district boundaries directly with the Portland planning or zoning department.

A published summary is never the authority. The adopted ordinance and the city's official zoning map govern, and both change — verify the district and every standard on your parcel before you rely on it.

How zoning works in Portland

Developers should watch for the citywide accessory dwelling unit allowances (expanded after Maine's 2022 statewide ADU law, LD 2003), shoreland zoning that overlays much of the peninsula and Back Cove waterfront with state-mandated setbacks and vegetation buffers, and a working waterfront zone that protects marine industrial uses along the harbor from residential conversion. Historic preservation review layers onto base zoning in several older neighborhoods and on the peninsula's historic districts.

Portland zoning districts by family

The 15 district codes below are the ones that decide most projects in Portland, grouped by what they are for rather than by the order the ordinance prints them.

Key districts in the Portland Land Use Code — a curated reference, not the exhaustive list. Confirm against the current adopted code.
Code	District	What it is for
Residential 6 districts
RN1	Residential Neighborhood 1
RN2	Residential Neighborhood 2
RN3	Residential Neighborhood 3
RN4	Residential Neighborhood 4
RN5	Residential Neighborhood 5
RN6	Residential Neighborhood 6
Mixed-use 1 district
TOD1	Transit-Oriented Development 1
Commercial 3 districts
AB	Auto-Oriented Business
B1	Business 1
B3	Business 3
Downtown / core 1 district
B6	Business 6
Industrial 3 districts
IL	Light Industrial
IM	Medium Industrial
IH	Heavy Industrial
Special purpose 1 district
OS-R	Open Space Recreation

Portland zoning — common questions

What does R-6 zoning mean in Portland, Maine?: R-6 is Portland's highest-density residential district, permitting multi-story apartment buildings at the smallest minimum lot area per unit in the code. It's concentrated in and around the peninsula's dense historic neighborhoods.
How do I find the zoning for an address in Portland, Maine?: Use the city's online zoning/GIS viewer, which returns the base district and any overlays (shoreland, historic, flood) for a given parcel. The Planning and Urban Development office can confirm interpretations for unusual lots.
Can I build an ADU in Portland, Maine?: Yes. Portland allows accessory dwelling units broadly following Maine's 2022 statewide ADU law, and the city eliminated many parking minimums for these units as part of a 2023 council vote — check current district-specific limits before designing.

Working in Maine? Get on the list.

The parcel layer lands in the order demand does. Illinois went first because that's where the deals were; the next state is decided by who tells us what they're trying to underwrite. Tell us where you're building and what you wanted to run — you'll hear from us when Maine opens, and sooner if we need a test parcel.

Keep reading

← Maine zoning — who holds the zoning power in Maine, under which enabling statute, and the reforms that override local rules.

Other Maine cities

The zoning reference → — every state, plus city-level district guides like this one.

Portland zoning summaries on this page are provided for information, not legal advice. Confirm every project against the current adopted code for the jurisdiction.