Build an ADU in Antrim.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Antrim — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
11 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Antrim zoning ordinance · source · 2026-07-07
- Front
- 30 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 35% building
- Min lot
- 60,000 sf (~1.38 ac)
The town's principal residential district (village area; per Art VI.A it essentially encompasses the portion of town served by municipal sewer and water). Min lot TIERS BY UTILITIES: 60,000 sf / 200 ft frontage / 200 ft depth WITHOUT public sewer+water (conservative tier…
- Front
- 30 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 35% building
- Min lot
- 60,000 sf (~1.38 ac)
Mixed-use village center; single-family, duplex and multifamily dwellings are permitted uses. Min lot TIERS BY UTILITIES: single-family 60,000 sf / 200 ft frontage / 200 ft depth WITHOUT public sewer+water (conservative tier recorded); 20,000 sf / 100 ft frontage / 100 ft…
- Front
- 50 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 40% building
- Min lot
- 90,000 sf (~2.07 ac)
Route 202/Route 9 corridor; single-family, duplex and multifamily dwellings are permitted uses. Values recorded are the conservative no-sewer/water tier of Art V.C.1: min lot 90,000 sf / 200 ft frontage / 200 ft depth, front 50 ft FROM THE STREET OR HIGHWAY RIGHT-OF-WAY line,…
- Front
- 50 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 40% building
- Min lot
- 60,000 sf (~1.38 ac)
Largest land-area district (rural residential/agricultural); single-family dwellings permitted by right. No public sewer/water tiering here — flat 60,000 sf min lot, 200 ft frontage, 200 ft depth for all uses except duplexes (85,000 sf / 300 ft frontage / 200 ft depth).
- Front
- 50 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- 40% building
- Min lot
- 90,000 sf (~2.07 ac)
Land within 500 ft of the high-water mark of Gregg Lake, Franklin Pierce Lake, Willard/Steele's/Rye/Campbell Ponds (Art VIII.D). Single-family by right; duplex only by special exception (130,000 sf / 300 ft frontage).
- Front
- 75 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- 25% building
- Min lot
- 130,000 sf (~2.98 ac)
Remote mountainous area north of Route 9 (Art II.B); single-family dwellings, farms and manufactured housing units permitted by right; duplexes NOT permitted (deleted 2005). Min lot 130,000 sf, 300 ft frontage, 300 ft depth.
- Front
- 100 ft
- Side
- 100 ft
- Rear
- 100 ft
- Max coverage
- —
- Min lot
- 653,400 sf (~15.00 ac)
OVERLAY north of Route 9 / east of a line 1,000 ft west of Liberty Farm Road, adopted 11-6-1990; adds hospitals, camps, shelter houses, conference centers, colleges and schools on top of the underlying district's uses.
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- —
- Min lot
- —
OVERLAY on the Rural District and all unserved (no public sewer+water) parts of other districts, mapped from the 1988 Town Slopes Map (slopes >15%). It raises MINIMUM LOT SIZE by slope where there is no public water+sewer and wetlands/steep slopes exist: single-family <=4…
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- —
- Min lot
- —
OVERLAY on all districts covering wetlands identified by soils/vegetation/wetlands maps. In unserved areas with wetlands/steep slopes the same soil-and-slope minimum lot sizes as the Steep Slopes overlay apply (single-family 68,000-86,000 sf by slope; Art XI.F).
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- 20% impervious
- Min lot
- —
OVERLAY within the protected shoreland of listed waterbodies (adopted 2003, amended through 2023). Impervious LOT COVERAGE capped at 20% (Art XI-A.J.3). New unserved lots: minimum size set by NHDES soil-based standards but never below the underlying district minimum; max one…
- Front
- 20 ft
- Side
- 15 ft
- Rear
- 15 ft
- Max coverage
- —
- Min lot
- 30,000 sf (~0.69 ac)
OPTIONAL overlay (adopted 3-11-2025) over the Village Business District and parts of the Residential District; applies ONLY if the applicant elects it via Planning Board CONDITIONAL USE PERMIT — otherwise underlying VB/R standards govern.
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Antrim ADU FAQ
Yes. Under NH RSA 674:71-73 (HB 577), one accessory dwelling unit is allowed by-right on single-family lots statewide, including Antrim (Hillsborough County). A detached ADU can be up to 950 sf.
In Antrim's R zone, ADUs follow the single-family setbacks: 30 ft front, 20 ft side, and 20 ft rear. Antrim has 11 zoning districts in total — see the full table below. Confirm your exact zone with the town.