ADU · Orange County
Can you build an ADU in Cornwall, NY?
Town of Cornwall has 11 districts. 8 districts allow ADUs with occupancy restrictions, 3 do not. Check your address to confirm the district that applies to your parcel:
What the Cornwall code indicates by district
The table below shows how each district treats ADUs, alongside the lot and setback standards that govern a second unit. District boundaries and conditions vary, so treat this as a starting point and confirm the district that applies to your parcel.
| District | Min lot | Setbacks F / S / R | Max height | ADU |
|---|---|---|---|---|
| Mountain Conservation Residential | 10 ac | 100 / 50 / 100 ft | 40 ft | Occupancy restricted |
| Agricultural Rural Residential | 3 ac | 75 / 30 / 75 ft | 40 ft | Occupancy restricted |
| Suburban Low-Density Residential | 2 ac | 60 / 30 / 60 ft | 40 ft | Occupancy restricted |
| Medium Residential | 2 ac | 60 / 30 / 60 ft | 40 ft | Occupancy restricted |
| Suburban Residential 1 | 1 ac | 50 / 30 / 40 ft | 35 ft | Occupancy restricted |
| Suburban Residential 2 | 0.46 ac | 30 / 15 / 30 ft | 35 ft | Occupancy restricted |
| Limited Service | 0.23 ac | 30 / 0 / 0 ft | 35 ft | No |
| General Commercial | 0.115 ac | 30 / 0 / 0 ft | 55 ft | No |
| Highway Commercial | 0.23 ac | 55 / 20 / 35 ft | 35 ft | Occupancy restricted |
| Planned Commercial Development | — | — | — | No |
| Planned Industrial/Office | — | — | — | Occupancy restricted |
ADUs vs. short-term rentals in Cornwall
Short-term rentals allowed with local rules for Town of Cornwall. Short-term rentals regulated under Local Law No. 3-2019 (Chapter 120). Permit required. These are separate questions from whether you can build an ADU — a unit you're allowed to add isn't automatically one you're allowed to rent nightly, so check both.
Good to know
- Residential lot minimum0.46–10 ac — an ADU still has to fit the district's lot and setback envelope.
- UtilityCentral Hudson territory.
- Building dept(845) 534-9429
- Last reviewed2026-07-08
ADU FAQ — Cornwall, NY
Are ADUs allowed in Cornwall, NY?
Town of Cornwall has 11 districts. 8 districts allow ADUs with occupancy restrictions, 3 do not. Check your address with the free ADU checker, or confirm with the building department at (845) 534-9429.
Do I need a special permit for an ADU in Cornwall?
No district in Town of Cornwall requires a special-use permit for an ADU - 8 districts allow ADUs with occupancy restrictions, 3 do not. Site-plan review or a building permit may still apply.
Can I use an ADU as a short-term rental in Cornwall?
Short-term rentals allowed with local rules for Town of Cornwall. ADU occupancy and short-term-rental rules are separate: an ADU you can build isn't automatically one you can rent nightly. Confirm both before you count on STR income.
What an ADU costs to build in Cornwall
Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $205k–270k at a standard finish, and the per-square-foot rate comes in above a full house because the kitchen, bath, panel and heating plant cost the same either way. See the full cost to build an ADU in Cornwall, priced by size.
More on Cornwall: Full zoning for new construction · ADU build cost · House build cost · All Orange County towns
ADU information for Town of Cornwall is compiled from the municipal code (last reviewed 2026-07-08) and provided for decision-support only — not legal or architectural advice. ADU eligibility, size, owner-occupancy and permit conditions vary by district and often carry exceptions; verify with the building department at (845) 534-9429 before relying on any answer. Source: Offsite / Aldo zoning dataset, municipalData.js.