Can I build a duplex on an R-1 lot in Billings?

Yes. Under Montana's 2023 Senate Bill 323, cities over 5,000 residents — including Billings — must allow duplexes anywhere single-family homes are permitted, so R-1 lots now permit duplex development by right regardless of the base district's historical single-family-only standard.

How do I find the zoning for a parcel in Billings, Montana?

The Planning & Community Services Division maintains the city's zoning map and regulations and can confirm the district for a specific address or parcel.

What does CBD zoning mean in Billings?

CBD is Billings' Central Business District, covering the downtown core and permitting the city's highest-intensity commercial and mixed-use development.

Billings, Montana · city zoning districts · 18 districts

Billings, MT zoning map & districts

Billings is Montana's largest city and, as of 2023, is directly subject to the state's duplex-by-right and ADU-by-right mandates under Senate Bills 323 and 528. The city's own zoning regulations — administered by the Planning & Community Services Division, with rezonings reviewed by the City Council after Planning Board recommendation — set the base district standards that those state mandates now override where they conflict, meaning single-family districts must permit duplexes and at least one accessory dwelling unit regardless of what the base district text otherwise says.

The code City of Billings Zoning Regulations

Billings zoning map

The city's Planning & Community Services Division maintains the zoning map and regulations text and handles parcel-level zoning verification.

There is no link to the official map here yet — confirm current district boundaries directly with the Billings 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 Billings

Billings' zoning districts follow a conventional residential-to-industrial gradient, with a distinct downtown business district and industrial zoning concentrated along its rail corridors and the Yellowstone River bottom near its refineries. Developers should confirm current district standards directly against the zoning ordinance, since the city has been amending individual district provisions to implement the 2023 state housing mandates.

Billings zoning districts by family

The 18 district codes below are the ones that decide most projects in Billings, grouped by what they are for rather than by the order the ordinance prints them.

Key districts in the City of Billings Zoning Regulations — a curated reference, not the exhaustive list. Confirm against the current adopted code.
Code	District	What it is for
Residential 9 districts
R150	Residential (15,000 sq ft min. lot)	Not in the original dataset; Billings' residential districts are lot-size-numbered, not R-1/R-2/R-3.
R96	Residential (9,600 sq ft min. lot)	Replaces dataset's non-existent 'R-1'; the city's most common single-family district.
R80	Residential (8,000 sq ft min. lot)	Not in the original dataset.
R70	Residential (7,000 sq ft min. lot)	Replaces dataset's non-existent 'R-2'.
R60	Residential (6,000 sq ft min. lot)	Not in the original dataset; the single most common residential district by parcel count.
R50	Residential (5,000 sq ft min. lot)	Not in the original dataset.
RMF	Residential Multi-Family	Replaces dataset's non-existent 'R-3'.
RMFR	Residential Multi-Family Restricted	Not in the original dataset.
RMH	Residential Manufactured Home	Confirmed.
Mixed-use 1 district
RP	Residential Professional Office	Not in the original dataset.
Commercial 3 districts
NC	Neighborhood Commercial	Confirmed.
CC	Community Commercial	Not in the original dataset; the largest commercial district by parcel count.
HC	Highway Commercial	Confirmed.
Downtown / core 1 district
CBD	Central Business District	Confirmed.
Industrial 2 districts
CI	Controlled Industrial	Replaces dataset's non-existent 'M-1' — Billings uses CI/HI, not an M- prefix.
HI	Heavy Industrial	Replaces dataset's non-existent 'M-2'.
Special purpose 2 districts
A1	Agricultural	Not in the original dataset.
PUD	Planned Unit Development	Not in the original dataset.

Billings zoning — common questions

Can I build a duplex on an R-1 lot in Billings?: Yes. Under Montana's 2023 Senate Bill 323, cities over 5,000 residents — including Billings — must allow duplexes anywhere single-family homes are permitted, so R-1 lots now permit duplex development by right regardless of the base district's historical single-family-only standard.
How do I find the zoning for a parcel in Billings, Montana?: The Planning & Community Services Division maintains the city's zoning map and regulations and can confirm the district for a specific address or parcel.
What does CBD zoning mean in Billings?: CBD is Billings' Central Business District, covering the downtown core and permitting the city's highest-intensity commercial and mixed-use development.

Working in Montana? 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 Montana opens, and sooner if we need a test parcel.

Keep reading

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

Other Montana cities

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

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