R9A Zoning District — New York City

Few designations in this file show as wide a gap between what stands and what is recorded as allowable. Across roughly 360 tax lots, 88% record floor area below their allowance, and the median residual runs to 4.4 FAR — a substantial recorded gap for a designation of this size. That headroom sits beneath an old, largely built-out fabric: 86% of buildings on record predate 1940, and the median construction year is 1915, deep in the prewar era. Only 4% of the recorded stock falls inside the 1945-1975 postwar boom, and just 7% has been built since 2000 — meaning most of the ground under this designation has stood, structurally, for over a century, even as the paperwork shows considerable unused capacity.

The recorded building classes lean toward walk-up apartment buildings, which account for 26% of the mix, followed by mixed residential-and-commercial buildings at 18% and elevator apartment buildings at 16% — a stock that pairs low-rise multi-family with a meaningful share of taller, mixed-use construction. Land use runs more concentrated: 48% of lots carry a mixed residential-and-commercial designation, essentially half the file, with multi-family walk-up use adding 12% and commercial-and-office use another 11%. Overall, 70% of these lots are coded residential, and the file counts 7,827 homes across them — a housing stock built as much through the ground-floor commercial pattern implied by that mixed-use majority as through purely residential parcels.

Lot sizes run modest at the middle and considerably wider at the edges: a median of 2,525 square feet against a 90th percentile of 12,500 square feet, a spread that points to a handful of substantially larger parcels sitting among the more typical small lots. Building heights track that same moderate scale — a median of 4 stories, with 21% of recorded buildings rising above 6 floors, a meaningful minority of taller construction layered onto an otherwise low- and mid-rise designation.

By the federal flood map, 9% of these lots sit inside the mapped Special Flood Hazard Area — a modest but non-trivial share, and a statement about the regulatory boundary rather than a record of which parcels have taken on water. Historic-district status is rarer here: just 3% of lots carry it on record, leaving most of this designation's roughly 360 parcels outside any landmark review layered on top of the zoning. Each lot carries its own version of every figure above, and the floor-area and height rules that actually govern this designation, cited section by section, are set out in the rules tables above this prose.