This map plots the parcels that New York City owns or leases and sorts each one by how ready it is to become housing. It was built to explore the same question the NYU Furman Center raised in its interactive maps of city-owned land: of all the land the city holds, how much could realistically hold new homes?
Two public datasets, both from NYC Open Data. COLP is published twice a year; this uses the edition released May 2026 (pulled July 2026).
fn4k-qyk2 holds 17,298 use-records, which sit on 15,188 distinct tax lots (about 1,600 lots carry more than one record). This map works at the lot level — see "From use-records to lots" below.64uk-42ks. A match was found for 15,107 of 15,188 lots (99.5%); the handful without a match show no size or zoning.COLP is a register of uses, not of parcels — a single tax lot can appear several times, once per agency or use. Counting the raw records would badly overstate things and mislabel land. The clearest example: John F. Kennedy Airport is one 214-million-square-foot tax lot that COLP records eight times (an airport, a pumping station, a tow pound, a wetland and three "no use" entries, among others). Rikers Island likewise carries both a "criminal justice facility" record and a "no use" record.
So this map first collapses the 17,298 records to their 15,188 distinct lots, and gives each lot a single category by precedence: if any record shows an active use, the lot takes that use and is not counted as vacant. Concretely — residential use wins first, then other active use, then parkland, and a lot is called "no current use" only when every one of its records is a no-use record. That keeps working airports, jails and parks out of the housing-opportunity bucket. A lot's popup notes when it combines more than one recorded use.
Dots vs. shapes. At a citywide view the map draws each lot as a coloured dot so the overall pattern is legible. Zoom in (to roughly the block level) and the dots are replaced by the real lot polygons, so you can see each site's true size and footprint — a NYCHA superblock, a park, or a sliver of a lot.
The 3D capacity view. The 3D capacity button tilts the map and extrudes each lot to a height proportional to its zoned residential floor-area ratio (FAR) — so a lot's buildable housing bulk reads as physical height. Tall blocks are lots zoned for dense housing; flat pads are lots with little or no as-of-right residential capacity (parks, or manufacturing and commercial lots that would need a rezoning). Combined with the "no current use" filter, it shows at a glance which vacant city sites carry the most as-of-right housing capacity. The height is a deliberately rough encoding of allowed density, not a building design: extruded height ≈ FAR × 13 metres, with a small minimum so every lot stays visible. Because FAR is floor area ratio, a taller box also stands for more total buildable floor area on that footprint.
Every lot is placed in one of four groups, using COLP's own category_code and expanded_category_code fields and the precedence rule above. The groups are ordered by how suitable the land is for new housing — the same framing the Furman Center used. Counts are distinct lots.
| Category | How it is defined here | Lots |
|---|---|---|
| No current use | Lots where every COLP record is "property with no use" — vacant land and unused structures. | 2,569 |
| Already residential | Any residential record — public housing, transitional and other homes on city land. | 1,183 |
| Other active use | Active non-residential use other than parks: offices, schools, depots, courts, garages, infrastructure, airports, jails and lots leased to private tenants. | 4,939 |
| Parks & natural areas | COLP's "cultural & recreational" use. In the raw data its largest component is actually wetlands and natural areas (the biggest single use type), followed by parks, community gardens, playgrounds and beaches, plus a few branch libraries — mostly protected from development. | 6,497 |
By lot, parks and natural areas account for about 43% of city lots, other active uses 33%, no current use 17%, and residential 8% — broadly the lot-shares the Furman Center reports (cultural/recreational over 40%, no-use around a fifth, residential under 10%). As a cross-check, the distinct lots here sum to 2.18 billion square feet, matching the Furman Center's "2.2 billion."
Why the no-use acreage looks small. The Furman Center reports "417 million square feet across nearly 3,000 lots" of no-use land; this map shows far fewer no-use acres. Two reasons, both deliberate. First, Furman counts a lot as no-use if it has any no-use record, so its 417M sq ft includes lots like the JFK Airport tax lot (214M sq ft on its own) that also carry active uses; the precedence rule here excludes those. Second, this map measures only the lots that are no-use through-and-through. The result — about 1,500 acres — is best read as a conservative floor on genuinely idle city land, not the ceiling.
For a lot with no current use that is zoned for housing, the popup shows a rough as-of-right capacity:
estimated homes ≈ (lot area × residential FAR) ÷ 1,000 sq ft
This is a deliberately simple back-of-envelope figure — it assumes about 1,000 square feet of building per home and takes the base residential FAR straight from zoning. It ignores height limits, setbacks, lot shape, bonuses, and every site-specific constraint. It is meant to separate "could plausibly hold real housing" from "could not," not to predict a project.
Where a no-use lot is not zoned for housing (residential FAR of zero), the map notes it would need a rezoning. Where a lot is smaller than 5,000 square feet, it flags that multifamily housing is difficult — echoing the Furman Center's point that most vacant city lots are small. In this data, 72% of no-use lots with a recorded size fall under that threshold, close to the Furman Center's reported 70%.
The map can colour each plot by its zoning instead of its housing readiness. Zoning comes from MapPLUTO's primary zoning district (ZoneDist1) for each lot, grouped into families by the leading letter of the code:
| Group | Codes | What it means for housing |
|---|---|---|
| Residential | R1–R10 | Housing is allowed as-of-right. The popup adds a rough density band (e.g. R6 = medium density). |
| Commercial | C1–C8 | Shops and offices; many commercial districts also permit residential use. |
| Manufacturing | M1–M3 | Industrial. Housing is generally not permitted without a rezoning. |
| Mapped parkland | PARK | Zoned as park; effectively off-limits to development. |
| Battery Park City | BPC | A special district administered by a state authority. |
| No zoning on record | — | No primary zoning district in the data (about 145 lots). |
This is why the "zoned for housing as-of-right" filter matters: of the 2,569 no-use lots, about 490 (326 manufacturing, 164 commercial) sit in districts that would need a land-use change before housing could be built as-of-right. The zoning shown is the lot's primary district only — lots split across two districts, commercial overlays and special-district rules are not reflected.
final_commitment = "D" field, DCP's marker that a lot may be disposed of by the city.This is a starting point, not a buildable-sites list.
A parcel's real development potential turns on contamination, easements, existing tenants and leases, air rights, community plans, landmarking and politics — none of which a tax-lot dataset captures. Parkland in particular is legally hard to build on. "No current use" means no use on record, which is not the same as empty or available. COLP is a point-in-time snapshot and lags real conditions. Verify any individual parcel against primary records before relying on it.
Every figure on this map was independently re-derived from the raw data and cross-checked against the live COLP API and the NYC Mayor's Office. That audit — which caught and corrected an inflated acreage figure and the record-vs-lot counting described above — is published as a versioned fact-check ledger.
Built with an AI coding assistant from public NYC Open Data. Not affiliated with the NYU Furman Center or the City of New York. Source data © the City of New York; basemap © OpenStreetMap and CARTO.
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