Build an ADU in Gilmanton.
New Hampshire's HB 577 lets you add one accessory dwelling unit on your single-family lot in Gilmanton — by-right. A detached ADU can be up to 950 sf, and ADU setbacks match your lot's single-family setbacks.
6 districts
Each district's single-family setbacks — which your ADU follows. The primary residential district is highlighted.
Verified against the official Gilmanton zoning ordinance · source · 2026-07-07
- Front
- 35 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 87,120 sf (~2.00 ac)
Primary residential district: the Rural Zone 'makes up the majority of area in town' (Art II); Gilmanton has no separate single-family-only district and single-family dwellings are permitted here. Min lot 2 acres (conventional) with 200 ft frontage on a Class V or better…
- Front
- 35 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
Two mapped village areas (Corners at Rte 140/Province Rd 107; Iron Works at Rte 140/Elm St) with mixed-use character. Min lot 1 acre with 125 ft frontage on a Class V or better road (Art II; Table 2). Front setback from ROW boundary, not centerline.
- Front
- 35 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
Area surrounding Sawyer Lake (off Province Rd/Rte 107 North); higher-density single-family zone, coterminous with the Sawyer Lake Village District. Min lot 1 acre with 125 ft frontage on a Class V or better road (Art II; Table 2).
- Front
- 50 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
Along Rte 140 West (Historic District to Allens Mill Rd) and Province Rd North (Copp Rd to Munsey Hill Rd); low-impact retail, small-scale service, light manufacturing, professional services. Min lot 1 acre with 200 ft frontage on a Class V or better road (Art II; Table 2).
- Front
- 50 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 43,560 sf (~1.00 ac)
Area on NH Route 106 intended to concentrate commercial/industrial growth. Min lot 1 acre with 200 ft frontage on NH Rte 106 (Table 2 notes frontage is on NH Rt. 106); open-space-subdivision frontage 125 ft on internal roads.
- Front
- 35 ft
- Side
- 20 ft
- Rear
- 20 ft
- Max coverage
- —
- Min lot
- 435,600 sf (~10.00 ac)
Northern section of town; purpose is preserving woodlands, wetlands and large contiguous forest tracts. Min lot 10 acres with 400 ft frontage on a Class V or better road (Art II; Table 2); open-space-subdivision lots may be 1 acre.
Form-based and downtown districts may use build-to lines instead of fixed setbacks (shown as “—”); verify your parcel's district before you build.
Gilmanton 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 Gilmanton (Belknap County). A detached ADU can be up to 950 sf.
In Gilmanton's R zone, ADUs follow the single-family setbacks: 35 ft front, 20 ft side, and 20 ft rear. Gilmanton has 6 zoning districts in total — see the full table below. Confirm your exact zone with the town.