R10 Zoning District — New York City

This designation pairs two facts that do not always travel together: an old recorded stock and a tall one. The median construction year is 1921, and 76% of buildings predate 1940 — a heavily prewar file — yet the median building height is 6 stories, with 50% of the recorded stock rising above 6 floors. The 1945-to-1975 postwar boom contributed only 13% of the file, and construction since 2000 adds a further 5%, so the tall, dense buildings this designation is best known for were, on the record, mostly built before the boom rather than during or after it.

A recorded 44% of these roughly 990 lots also carry historic-district status — one of the higher overlaps of any designation profiled in this batch — layered directly on top of that old, tall building stock. By land use, multi-family elevator buildings lead at 35%, mixed residential-and-commercial use follows at 31%, and one- and two-family use adds 10%. Among recorded building classes, elevator apartment buildings account for 40%, walk-up apartment buildings 18%, and condominiums 9% — a composition dominated by multi-unit, elevator-served structures rather than smaller walk-up or single-family stock.

Eighty-four percent of these lots are coded residential, and the file counts 53,904 units on record — a very large total for a designation of only about 990 lots, consistent with the tall, elevator-served building classes recorded above. Lots themselves run to a median of 5,133 square feet, with the 90th percentile reaching 20,400 square feet, ground large enough to carry the taller buildings the height file already shows.

Three percent of these lots sit inside the mapped federal flood zone, a modest share alongside the substantial historic-district overlap noted above. Floor-area headroom is recorded on a majority but not the near-totality seen on some other designations: 67% of lots record built area below their allowance, with a median residual of 5.1 FAR — a wide gap in absolute terms, consistent with a designation built for considerable height. The specific allowance behind that figure, with its citation, is set out in the rules tables above.

Set beside the historic-district and headroom figures above, the age and height combination here reads as a designation whose tallest, densest development mostly predates the postwar boom rather than followed from it. With 84% of lots coded residential and a unit count, 53,904, large for only about 990 lots, the elevator-served building classes described above are carrying most of that housing on a relatively small physical footprint rather than a broad one.