Build an ADU in Greenfield.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Greenfield — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
8 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Greenfield zoning ordinance · source · 2026-07-07
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Default district: 'encompasses all land not contained in any other district' plus 400-ft corridors where major roads penetrate other districts (III.D.4). Primarily residences; no restriction on residential building type if lot/frontage/setbacks met.
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 174,240 sf (~4.00 ac)
Min lot 4 acres; frontage 350 ft Front yard 100 ft from the nearest side of any public highway (edge, not centerline); side and rear 50 ft Pre-existing recorded undersized lots deemed conforming with setbacks reduced in proportion to (actual lot size / 4 acres), but never…
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Primarily residential. Min lot 2 acres; frontage 250 ft on a Class V or better highway. Front yard 100 ft from the nearest side of any public highway (edge, not centerline); side and rear 50 ft Pre-existing recorded undersized lots deemed conforming with setbacks reduced in…
- Front
- 100 ft
- Side
- 50 ft
- Rear
- 50 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Residences only; comprises all land within 400 ft of the high-water mark of Otter, Sunset and Zephyr Lakes (III.C.4). Min lot 2 acres; frontage 250 ft on a Class V or better highway. Front yard 100 ft from the nearest side of any public highway (edge, not centerline); side…
- Front
- —
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 10,890 sf (~0.25 ac)
Village business core around Forest/Sawmill/Slip Roads. Min lot 1/4 acre; frontage 65 ft; pre-existing recorded smaller lots deemed conforming. FRONT SETBACK IS NOT A FIXED NUMBER: it is the 'build-to' line, defined in Section II.E as the distance from the nearest edge of the…
- Front
- 100 ft
- Side
- 50 ft
- Rear
- —
- Max coverage
- 30% building
- Min lot
- —
Special Purpose District superimposed over defined areas of the General Residence District (Russell Station area and Sawmill Road/Route 31 area); where superimposed, the more restrictive regulations apply.
- Front
- —
- Side
- —
- Rear
- —
- Max coverage
- —
- Min lot
- —
Overlay over all districts covering poorly/very poorly drained (Hydric A/B) soils and water bodies per the 1970 National Cooperative Soil Survey mapping; more restrictive regulation governs where superimposed.
- Front
- 30 ft
- Side
- —
- Rear
- —
- Max coverage
- 70% building
- Min lot
- —
Special Purpose District (adopted 2011, amended 2012) on 12 listed R2 tax lots; where it conflicts with the underlying General Residence District, CMREC use regulations and dimensional requirements 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.
Greenfield 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 Greenfield (Hillsborough County). A detached ADU can be up to 950 sf.
In Greenfield's GR zone, ADUs follow the single-family setbacks: 100 ft front, 50 ft side, and 50 ft rear. Greenfield has 8 zoning districts in total — see the full table below. Confirm your exact zone with the town.