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/NEWMARKET

Newmarket ZIP code, New Hampshire

The ZIP code for Newmarket, NH is 03857, and its area code is 603.

USPS city name
1 ZIP code
Population
5,679
Area code
603

Newmarket in numbers

About 5,679 people live in Newmarket, in 2,840 households, the 24th-largest of New Hampshire's 100 census places. The median household income is $87,196 a year, 12% below the New Hampshire median of $99,031 (US: $80,734). The median owner-occupied home is valued at $423,500 (5% above the New Hampshire median), and median gross rent is $1,701 a month. The median age is 38.3; 48.9% of adults 25 and over hold a bachelor's degree or higher (40.6% across New Hampshire); the average commute takes 29 minutes.

Population5,679Newmarket5,679
Households2,840Newmarket2,840
Median age38.3Newmarket38.3New Hampshire43.3US 38.9
Median household income$87,196Newmarket$87,196New Hampshire$99,031US $80,734
Median home value$423,500Newmarket$423,500New Hampshire$402,500US $332,700
Median gross rent$1,701Newmarket$1,701New Hampshire$1,491US $1,413
Bachelor's degree or higher48.9%Newmarket48.9%New Hampshire40.6%US 35.7%
Mean commute28.7 minNewmarket28.7 minNew Hampshire26.7 minUS 26.4 min
Population density2,523 / sq miNewmarket2,523 / sq mi

U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, for the census place Newmarket CDP. Survey estimates carry margins of error, wider for small places. Sources and methods.

ZIP codes addressed as Newmarket

ZIP codes with the USPS city name Newmarket
ZIP City Type Population Median income Median home
03857 Newmarket , NH Standard 9,463 $100,845 $455,000

Map of Newmarket ZIP codes

03857

The ZIP codes of Newmarket, 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 Newmarket

The nearest larger towns are Durham (10,681 people, 4.7 mi), Exeter (9,964 people, 6.8 mi) and Portsmouth (22,545 people, 8.2 mi).

Towns near Newmarket
TownPopulationDistance
Durham 10,681 4.7 mi
Exeter 9,964 6.8 mi
Portsmouth 22,545 8.2 mi
Dover 33,364 8.2 mi
Epping 2,796 8.4 mi
South Eliot, ME 4,203 8.5 mi
Kittery, ME 5,110 10.3 mi
Hampton 10,101 10.8 mi
Raymond 3,645 12.2 mi
Somersworth 12,111 12.6 mi
South Berwick, ME 3,381 12.9 mi
Hampton Beach 2,605 12.9 mi
Rochester 33,144 15.5 mi
York Harbor, ME 4,240 15.5 mi

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

Cite this page

zipcodes.pro. “Newmarket, NH ZIP codes.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/city/nh/newmarket

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