C6-4M Zoning District — New York City

The building-year records for this designation skew about as old as anything on the city's rolls: 81% of the recorded stock predates 1940, and the median construction year is 1915 — a generation before the current zoning code existed. Only 2% of buildings date from the 1945-to-1975 building boom, and 13% have gone up since 2000, so what modern construction there is has come recently and in small increments rather than in a postwar wave. Layered on top of that age is a designated historic district covering 38% of these lots — landmark review sitting directly on top of the zoning here, on roughly 170 tax lots citywide. Few of the designations covered on these pages combine that much recorded age with that much recorded landmark coverage inside the same file.

By recorded building class, office buildings are the largest single category at 40% of the stock, with elevator apartment buildings holding another 13%; the rest of the mix runs across other recorded classes not further coded on this page. Land use tells a similar story: 56% of lots are logged under commercial and office use, 18% under mixed residential-and-commercial use, and 10% under multi-family elevator-building use. Only 35% of lots are recorded as residential outright, and the file counts 7,806 housing units on that residential share — a commercial-leaning designation with a meaningful residential minority tucked inside it, substantial in absolute count even where the land-use labels lean toward offices.

The lots themselves run to a median of 4,937 square feet, with the 90th percentile reaching 15,487 square feet — a moderate, unremarkable lot fabric by citywide standards next to some of the wider spreads recorded elsewhere in this set. What stands on them, though, runs taller than the age profile alone would suggest: a median height of 10 stories, with 63% of recorded buildings rising above 6 floors. That combination — a prewar median construction year alongside a double-digit median floor count — describes a stock built up incrementally over time on a fairly fixed lot base, adding height in later decades rather than expanding outward.

On development capacity, the records show 56% of lots with floor area recorded below their allowance, with a median gap of 1.6 — moderate and broadly distributed rather than concentrated in a handful of parcels. None of the lots carrying this designation, 0%, fall inside the mapped federal flood zone on the current federal map — a statement about the map, not a guarantee about water. The specific caps and citations behind those gaps sit in the rules tables above, keyed to each parcel; what is recorded here is the stock itself, lot by lot, as it stands today rather than as it might later be built out.