What is on the map today.

All five boroughs are on the map, and the rest is honest about itself. This page is generated from the same records the map reads, so the counts below are what is actually loaded rather than what was loaded when someone last edited a paragraph.

857,347

Tax lots

Every lot on the city tax map

1,083,016

Buildings

Footprints from the city's aerial survey

3,735,269

Homes of record

Residential units across every lot

198

Neighborhoods

Each with its own page and its own streets

New York City, complete.

Phase 0 was a deliberate choice to build the universe before the crawler: load every place in the city from its own files, give each one a permanent URL, and only then start collecting what is for sale. A property site that starts with listings has nothing to attach them to, and every page it publishes disappears when the listing does.

The unit of coverage is the place, and there are three kinds. A tax lot is a piece of ground with a BBL. A building is a structure standing on one, with its own BIN. A home is an individual apartment inside a building, which exists as a separate place only where the city's condominium records make it addressable.

One address, three recordslot / building / home

Tax lot
The ground
BBL 1008350041
What a deed is recorded against. One lot, one BBL, forever.
Building
350 5th Avenue
BIN 1015862
A structure standing on the lot, with its own footprint and height.
Home
Unit 4B
Its own deed
Addressable only where the city's condominium records make it so.

A deed recorded against the lot is not the sale of one apartment. Every page here says which of the three a number belongs to, because the difference is usually a factor of a hundred.

Four city files, joined on one identifier.

The spine is PLUTO, the Department of City Planning's tax lot file: one row for every lot in the city with its zoning, its land use, its lot area, its floor count and its year built. Each row is keyed by BBL - borough, block and lot - which is the city's permanent identifier for a piece of ground, and it is the join key everything else hangs off.

Building footprints come from the city's aerial survey, one row per structure keyed by BIN, carrying the outline and the measured roof height. Address points supply the street names and house numbers that turn a lot into an address, and they are also where alternate addresses come from: the Empire State Building answers to 350 5th Avenue, 1 West 33rd Street and 2 West 34th Street, and all three resolve to the same record here.

Sales come from ACRIS, the city register of recorded documents, where a deed is filed when a property changes hands. Condominium homes come from the Digital Tax Map, which is what makes an individual apartment addressable at all - without it a condominium is one billing lot and 95,174 homes have nowhere to live on the map.

Four questions asked of every number.

None of these is exotic. They are what a careful researcher would ask, written down so they are asked the same way every time, on every one of 995,043 addresses.

Which file said so?

Every fact traces to a named city dataset and the date it was loaded. A number with no file behind it does not render at all.

Against what was it recorded?

A deed is filed against a tax lot; a reader is looking at a building or a home. Every price says which, because on a condominium billing lot one deed can cover several buildings.

Was it an arm's length sale?

A one dollar transfer between family members is a real record and a meaningless price. It is shown, labelled, and kept out of every median.

How wrong can it be?

Year built is good to the decade. Building area is a rough gross figure. Where a source has a known weakness, it is written next to the number rather than in a footnote.

What is checked before a record exists.

A place gets a URL only when the city's own files agree on where it is. A lot with no addressable building, a footprint that lands outside every lot, or an address point matching no structure is written to a rejection log rather than guessed into place - 398 of Manhattan's 42,504 lots were refused on those grounds, and refusing them is why the other 42,106 can be trusted.

Sales are matched to places by BBL, and the match is not always possible: 4,636 deed lots in the register correspond to no lot in the current tax file, because lots merge, split and cease to exist while the deeds recorded against them do not. Those deeds are held rather than forced onto the nearest plausible address.

A recorded price is not automatically a sale price. New York State's own test treats a consideration of ten dollars or less as a transfer rather than a sale, and applying it moved the median arm's length Manhattan sale from 4.4 million dollars to 1,400,094 - the first number was a median of family transfers and restructurings mixed in with real deals.

What this method cannot tell you.

Public record is a record of paperwork, not of life. A home that changed hands through a share transfer in a cooperative leaves no deed against the apartment, so a co-op's record shows the building's history and not the unit's. That is a large share of the pre-war housing stock in New York, and no amount of care with the data changes it.

The record is also late. A deed reaches ACRIS weeks or months after a closing, and until it does the last recorded sale is the previous one. Nothing here is a live market feed, and the asking prices arriving in phase 1 will be a different kind of fact with a different lag.

Finally, we do not know what a building is like. The city records its height, its age and its zoning; it does not record whether the elevator works, and neither do we. There are no valuations here for the same reason - an estimate is a claim about somebody's money, and the honest product is the record itself.

Every neighborhood has its own page.

And so does every street inside it, and every building on every street. This is the layer that makes the map crawlable: an address is reachable by following links, not only by clicking a shape.

Brooklyn

Queens

Staten Island

Two more boroughs, then prices.

The other four boroughs are the same four city files and a larger database, and the work is a day of loading rather than a new design. It is deferred rather than blocked: with no asking prices yet, a second borough adds pages without adding anything a reader could not already get.

Phase 1 is the part that changes the product. Asking prices from the portals and listings posted directly here attach to places that already exist, which is why the schema for them is already built and returning empty arrays. When they arrive, no page on this site changes shape - a section that is empty today fills in.

Open the map.

Every tax lot, every building and every home in all five boroughs is on it, and each one has its own permanent address. Click a building to see what the city actually knows about it.

Open the map Search an address