10521

ZIP 10521 is in Croton On Hudson, New York, in Westchester County; area code 914; Eastern time. Croton On Hudson has 2 ZIP codes; the other is 10520.

Type: No street area
Time zone: America/New_York
County: Westchester
Metro area: New York-Newark-Jersey City, NY-NJ
Coordinates: 41.2343, -73.9262

The Census map gives this ZIP code no delivery area of its own, which usually means it serves post office boxes, a single organization or a post office rather than streets of homes.

This ZIP code has no Census tabulation area of its own. Its point falls inside ZCTA 10520, whose figures describe that area — not this ZIP code.

☼ Live from 10521 — Croton On Hudson, NY

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Where 10521 is

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This ZIP code has no Census tabulation area, so there is no boundary to draw — the marker is its published point location.

★ Weird and wonderful facts about 10521

🔢 Type 10521 into a pocket calculator and turn it upside down: IZSOI — not quite a word, sorry.
➕ As a number, 10,521 = 3 × 3 × 7 × 167. Its digits add up to 9, a total 375 other ZIP codes share.
💾In binary, the way a computer stores it: 10100100011001
🏠 Its numerical neighbours: 10520 (Croton On Hudson, NY, 3 mi away) and 10522 (Dobbs Ferry, NY, 16 mi away).
🔄 Backwards, 10521 becomes 12501 — and that is a real ZIP code: Amenia, NY, 47 miles away.
👥 37 other ZIP codes are made of exactly the same digits (01152, 01521, 02115, 02151, 10125, 10152, …). The farthest-flung twin is 51102 in Sioux City, IA, 1,153 miles away.
🧭 Farther north than 69% of all ZIP codes, and farther east than 91%.
🎯1,294 miles east of the geographic center of the Lower 48, near Lebanon, Kansas.
🌏 Dig straight through the Earth from 10521 and you would come out at 41.23°S, 106.07°E — 839 miles from Perth, Australia, the nearest big city to that spot.
☀Longest day of the year: 15h 09m of daylight. Shortest: 9h 12m.

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Source: USGS.

Land area

ZIP codes near 10521

ZIP	City	Distance
`10548`	Montrose, NY	1.0 mi
`10511`	Buchanan, NY	2.2 mi
`10596`	Verplanck, NY	2.3 mi
`10993`	West Haverstraw, NY	3.0 mi
`10520`	Croton On Hudson, NY	3.1 mi
`10927`	Haverstraw, NY	3.7 mi
`10566`	Peekskill, NY	3.8 mi
`10567`	Cortlandt Manor, NY	4.1 mi
`10923`	Garnerville, NY	4.5 mi
`10986`	Tomkins Cove, NY	5.2 mi

Find every ZIP code within 10 miles of 10521 →

Questions about this ZIP code

Where is ZIP code 10521?

10521 is in Croton On Hudson, New York, in Westchester County, part of the New York-Newark-Jersey City, NY-NJ metropolitan area. Its published point location is 41.2343, -73.9262.

What county is 10521 in?

10521 lies in Westchester County.

What area code is 10521?

Croton On Hudson uses area code 914, from NANPA's telephone records.

What time zone is 10521 in?

10521 uses America/New_York.

What ZIP codes are near 10521?

The closest are 10548 (1 mi), 10511 (2.2 mi), 10596 (2.3 mi), 10993 (3 mi) and 10520 (3.1 mi).

Is 10521 a PO Box ZIP code?

Possibly. The Census map gives this ZIP code no delivery area of its own, which usually means it serves post office boxes, a single organization or a post office rather than streets of homes.

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Cite this page

zipcodes.pro. “10521 ZIP Code — Croton On Hudson, New York (Westchester County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/10521

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/10521.json

Underlying data is public domain or openly licensed — sources, vintages and licences.