00721

ZIP 00721 is Palmer, Puerto Rico, in Río Grande Municipio; area codes 787 and 939; Atlantic time.

Type: No street area
Time zone: America/Puerto_Rico
County: Río Grande
Metro area: San Juan-Bayamón-Caguas, PR
Coordinates: 18.3705, -65.7741

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 00745, whose figures describe that area — not this ZIP code.

☼ Live from 00721 — Palmer, PR

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Where 00721 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 00721

🔢 Type 00721 into a pocket calculator and turn it upside down: IZLOO — not quite a word, sorry.
➕ As a number, 721 = 7 × 103. Its digits add up to 10, a total 513 other ZIP codes share.
💾In binary, the way a computer stores it: 1011010001
🏠 Its numerical neighbours: 00720 (Orocovis, PR, 44 mi away) and 00723 (Patillas, PR, 28 mi away).
🔄 Backwards, 00721 becomes 12700, which is not a ZIP code at all.
👥 27 other ZIP codes are made of exactly the same digits (01027, 01072, 01270, 01702, 01720, 02071, …). The farthest-flung twin is 72001 in Adona, AR, 2,021 miles away.
🧭 Farther south than 99% of all ZIP codes, and farther east than 98%.
🎯2,451 miles southeast of the geographic center of the Lower 48, near Lebanon, Kansas.
🌏 Dig straight through the Earth from 00721 and you would come out at 18.37°S, 114.23°E — 675 miles from Denpasar, Indonesia, the nearest big city to that spot.
☀Longest day of the year: 13h 14m of daylight. Shortest: 11h 01m.

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Source: USGS.

Land area

ZIP codes near 00721

ZIP	City	Distance
`00745`	Rio Grande, PR	2.7 mi
`00773`	Luquillo, PR	3.8 mi
`00738`	Fajardo, PR	6.7 mi
`00729`	Canovanas, PR	7.8 mi
`00718`	Naguabo, PR	9.6 mi
`00740`	Puerto Real, PR	9.7 mi
`00772`	Loiza, PR	9.8 mi
`00744`	Rio Blanco, PR	10.6 mi
`00735`	Ceiba, PR	10.8 mi
`00987`	Carolina, PR	11.3 mi

Find every ZIP code within 10 miles of 00721 →

Questions about this ZIP code

Where is ZIP code 00721?

00721 is in Palmer, Puerto Rico, in Río Grande Municipio, part of the San Juan-Bayamón-Caguas, PR metropolitan area. Its published point location is 18.3705, -65.7741.

What county is 00721 in?

00721 lies in Río Grande Municipio.

What area code is 00721?

Palmer uses area codes 787 and 939, from NANPA's telephone records.

What time zone is 00721 in?

00721 uses America/Puerto_Rico.

What ZIP codes are near 00721?

The closest are 00745 (2.7 mi), 00773 (3.8 mi), 00738 (6.7 mi), 00729 (7.8 mi) and 00718 (9.6 mi).

Is 00721 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. “00721 ZIP Code — Palmer, Puerto Rico (Río Grande Municipio).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/00721

Machine-readable version of these facts:

curl https://zipcodes.pro/zip/00721.json

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