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 — CITY/NH/NEW-CASTLE

New Castle ZIP code, New Hampshire

The ZIP code for New Castle, NH is 03854, and its area code is 603.

USPS city name
1 ZIP code
Population
827
Area code
603

NANPA lists no telephone rate centre for New Castle itself, so these are the area codes of the nearest one, Portsmouth (2.4 miles). A town on an area-code boundary can differ from its neighbour.

New Castle in numbers

About 827 people live in New Castle, in 401 households. The median household income is $176,953 a year, 79% above the New Hampshire median of $99,031 (US: $80,734). The median owner-occupied home is valued at $1,701,300 (4.2 times the New Hampshire median).

Population827New Castle827
Households401New Castle401
Median household income$176,953New Castle$176,953New Hampshire$99,031US $80,734
Median home value$1,701,300New Castle$1,701,300New Hampshire$402,500US $332,700

U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, for the ZIP code addressed as New Castle. Survey estimates carry margins of error, wider for small places. Sources and methods.

ZIP codes addressed as New Castle

ZIP codes with the USPS city name New Castle
ZIP City Type Population Median income Median home
03854 New Castle , NH Standard 827 $176,953 $1,701,300

Map of New Castle ZIP codes

03854

The ZIP codes of New Castle, NH, shaded. Outlines are Census ZIP Code Tabulation Areas (2020), which approximate the mail routes; PO-box and single-address codes have no area and are not drawn. Click any area to open its ZIP code.

Towns near New Castle

The nearest larger towns are Kittery, ME (5,110 people, 2.2 mi), Kittery Point, ME (935 people, 2.6 mi) and Portsmouth (22,545 people, 3.2 mi).

Towns near New Castle
TownPopulationDistance
Kittery, ME 5,110 2.2 mi
Portsmouth 22,545 3.2 mi
South Eliot, ME 4,203 6.3 mi
York Harbor, ME 4,240 6.6 mi
Hampton 10,101 9.8 mi
Hampton Beach 2,605 11.3 mi
Newmarket 5,679 11.3 mi
Durham 10,681 11.9 mi
Dover 33,364 12.0 mi
South Berwick, ME 3,381 12.3 mi
Exeter 9,964 13.0 mi
Somersworth 12,111 15.8 mi
Salisbury, MA 5,656 17.3 mi
Amesbury, MA 17,403 18.9 mi

More nearby: every ZIP code in Rockingham County · New Hampshire ZIP codes

Cite this page

zipcodes.pro. “New Castle, NH ZIP codes.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/city/nh/new-castle

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