Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — ZIP/78683

78683

ZIP 78683 is in Round Rock, Texas, in Williamson County; area codes 512 and 737; Central time. Round Rock has 6 ZIP codes; the others are 78664, 78665, 78680, 78681 and 78682.

Type
No street area
Time zone
America/Chicago
County
Williamson
Coordinates
30.6568, -97.6026

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 78626, whose figures describe that area — not this ZIP code.

☼ Live from 78683 — Round Rock, TX

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Where 78683 is

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 78683
  • 🔢 Type 78683 into a pocket calculator and turn it upside down: EBgBL — not quite a word, sorry.
  • ➕ As a number, 78,683 = 11 × 23 × 311. Its digits add up to 32, a total 644 other ZIP codes share.
  • 💾In binary, the way a computer stores it: 10011001101011011
  • 🏠 Its numerical neighbours: 78682 (Round Rock, TX, 0 mi away) and 78691 (Pflugerville, TX, 15 mi away).
  • 🔄 Backwards, 78683 becomes 38687, which is not a ZIP code at all.
  • 👥 20 other ZIP codes are made of exactly the same digits (37688, 37868, 37886, 38768, 38876, 63878, …). The farthest-flung twin is 83876 in Worley, ID, 1,548 miles away.
  • 🧭 Farther south than 91% of all ZIP codes, and farther west than 76%.
  • 🎯636 miles south of the geographic center of the Lower 48, near Lebanon, Kansas.
  • 🌏 Dig straight through the Earth from 78683 and you would come out at 30.66°S, 82.40°E — 1,439 miles from Port-aux-Français, French Southern Territories, the nearest big city to that spot.
  • ☀Longest day of the year: 14h 08m of daylight. Shortest: 10h 10m.
🌙 The sky over 78683 today
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🌋 Shake report
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Source: USGS.

Business and tax activity

Business establishments27This ZIP27
Employees267This ZIP267
Annual payroll$9,243,000This ZIP$9,243,000

Land area

ZIP codes near 78683

ZIPCityDistance
78680 Round Rock, TX 0.0 mi
78682 Round Rock, TX 0.0 mi
78626 Georgetown, TX 0.9 mi
78674 Weir, TX 1.0 mi
78627 Georgetown, TX 4.7 mi
78673 Walburg, TX 5.9 mi
78634 Hutto, TX 7.5 mi
78665 Round Rock, TX 7.7 mi
78681 Round Rock, TX 10.4 mi
78628 Georgetown, TX 10.5 mi

Find every ZIP code within 10 miles of 78683 →

Questions about this ZIP code

Where is ZIP code 78683?

78683 is in Round Rock, Texas, in Williamson County, part of the Austin-Round Rock-San Marcos, TX metropolitan area. Its published point location is 30.6568, -97.6026.

What county is 78683 in?

78683 lies in Williamson County.

What area code is 78683?

Round Rock uses area codes 512 and 737, from NANPA's telephone records.

What time zone is 78683 in?

78683 uses America/Chicago.

What ZIP codes are near 78683?

The closest are 78680 (0 mi), 78682 (0 mi), 78626 (0.9 mi), 78674 (1 mi) and 78627 (4.7 mi).

Is 78683 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. “78683 ZIP Code — Round Rock, Texas (Williamson County).” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/zip/78683

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