C4-3A Zoning District — New York City

This designation's construction record is consistently prewar: of the roughly 700 lots mapped this way, 94% of recorded buildings predate 1940 and the median construction year is 1930 — among the oldest, most uniform records of this kind. The 1945-to-1975 boom left almost no mark here, at just 2% of the stock, and construction since 2000 has added only 3% more. The picture is of a fabric substantially built out before the Depression, with only the lightest infill in the century since and no real second wave of construction at any point. Unlike designations built up across several eras, this one shows a construction record concentrated almost entirely in one — the prewar period — with everything since amounting to only a light trickle on top of that base.

The composition matches the age: mixed residential-commercial buildings account for 67% of recorded land use, by far the largest single category, with commercial-and-office uses adding 15% and multi-family walk-up buildings a further 12%. Among recorded building classes, mixed residential-commercial structures make up 48% of the stock and walk-up apartment buildings 16% more. Residential lots make up 82% of the total — a high share — and the file counts 6,344 homes across these roughly 700 lots, a dense figure for a district this size. That residential share, among the highest recorded in this profile, pairs with the prewar concentration described above to describe a stock that has changed remarkably little in composition even as decades passed.

The lot fabric is unusually tight: a median of 2,375 square feet, with the 90th percentile reaching only 5,000 square feet — a narrow spread between typical and large parcels, meaning even the bigger lots here stay close to the norm. Buildings run to a median height of 3 stories, and just 1% of the recorded stock rises above 6 floors. A recorded 10% of lots sit inside a designated historic district, a meaningful landmark overlay layered on top of the zoning, while only 2% fall within the mapped federal flood zone. That tight lot fabric limits how much any individual parcel could realistically absorb beyond what is already recorded, which helps explain why the development gap described below stays modest even where it is broadly distributed.

The development ledger shows broad but shallow slack: 83% of lots record floor area below their allowance, though the median residual is just 0.9 FAR — real headroom, but on parcels too small and too uniform to make assembly easy. Because the underlying lots run this small and this uniform, that recorded headroom is more likely to show up as modest additions or renovations on individual buildings than as wholesale redevelopment. The specific allowance behind that figure, and its citation, is in the rules tables above; each lot's own page carries the recorded numbers for that parcel alone.