| City: | New Castle, New Hampshire |
| Names to Avoid: | Newcastle |
| County: | Rockingham County |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 7:58:53 PM |
| Population: | 1,000 [See All] |
| Area Code: | 603 |
| Classification: | PO Box |
| Coordinates: | 43.0642, -70.7227 |
| Land Area: | 0.809 sq mi |
| Quick Link: |
New Castle occupies a small island at the mouth of the Piscataqua River on New Hampshire's seacoast. With a population of 1,000 spread across just 1.1 square miles, this town is one of the state's most exclusive coastal communities. The median home value of $1,612,700 and household income of $193,558 put New Castle among New Hampshire's wealthiest enclaves.
Nearly everyone relies on PO Boxes. The post office maintains 536 boxes for 459 households, a 117% adoption rate that accounts for seasonal residents, second homeowners, and businesses. This is a PO Box Only Zone. There's no alternative mail delivery across the island. Rural carrier route delivery serves only a handful of addresses, while most residents pick up mail at the post office.
The median age is 60.8 years, making New Castle a retirement community. Only 1% of residents are under 18, while 18% are 65 or older. With 71% holding bachelor's degrees or higher and 28% working from home, this is an educated population of professionals, retirees, and remote workers.
Street names tell the island's maritime story. Wentworth Road has the most delivery points (13 records), followed by Main Street (9 records) and Wild Rose Lane (6 records). Coastal names like Ocean Street, Harborview Street, Little Harbor Road, Marina Heights Road, and Steamboat Lane dot the landscape. Historic character runs deep. Of the 459 occupied homes, 517 were built before 1939, meaning nearly every structure predates World War II.
The town's 21 business establishments employ 339 workers, many commuting from the mainland. Transportation and warehousing account for an unusual 365 workers in ACS data, likely tied to Portsmouth Harbor shipping activity. Federal government workers number 45, possibly connected to the nearby Portsmouth Naval Shipyard.
New Castle has limited seasonal housing compared to vacation islands. Only 51 of 525 total housing units (9.7%) are for seasonal use. This is primarily a year-round community, not a summer colony. The high owner-occupancy rate (88% of occupied homes) confirms permanent residency patterns.
All mail must use PO Box addresses:
[Name]
PO Box [Number]
New Castle, NH 03854The alternative spelling "Newcastle" (one word) is recognized by USPS but isn't valid for mailing. Use "New Castle" (two words) for all mail.
Maritime names dominate: Ocean Street, Harborview, Little Harbor Road, Marina Heights, and Steamboat Lane capture the island's coastal identity.
ZIP Code 03854 has 1,000 residents and 459 households (average 2.18 persons per household). The median age is 60.8 years, significantly older than the state (43.6) and significantly older than the nation (38.8). The gender split is 47.7% male and 52.3% female, which is slightly lower than the state male share (49.5%), making this a female-majority area. Largest groups are White (94.9%, much higher than the national average of 61.6%) and Hispanic or Latino (2.7%); Hispanic or Latino residents make up 2.7%, which is much lower than the national average (18.7%).
Explore More: Population Over Time By Age & Gender By Race By Gender Nativity & Citizenship
| 2020 Population: | 1,000Source: Census DHC |
| 2024 ACS Population Estimate: | 827Source: Census ACS |
| 2026 ZC Population Estimate: | 0Source: ZIP-Codes.com |
| Population Density: | 1,236.1 people per sq mile |
| Average Income: | $176,953Source: Census ACS |
| Households: | 459Source: Census DHC |
| Average House Value: | $1,701,300Source: Census ACS |
| Persons Per Household: | 2.18Source: Census DHC |
| Average Family Size: | 2.73Source: Census ACS |
| Group | 2010 | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Census ACS Population Estimate | -- | 941 | 990 | 930 | 980 | 974 | 935 | 917 | 780 | 835 | 863 | 817 | 904 | 948 | 827 |
| Decennial Census | 968 | -- | -- | -- | -- | -- | -- | -- | -- | -- | 1,000 | -- | -- | -- | -- |
Median Age: 60.8
Male Median Age: 59.6
Female Median Age: 61.3
| Group | < 5 | 5-9 | 10-14 | 15-19 | 20-24 | 25-29 | 30-34 | 35-39 | 40-44 | 45-49 | 50-54 | 55-59 | 60-64 | 65-69 | 70-74 | 75-79 | 80-84 | 85+ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Male | 10 | 13 | 18 | 29 | 28 | 12 | 9 | 9 | 6 | 18 | 33 | 56 | 53 | 70 | 38 | 34 | 24 | 17 |
| Female | 4 | 7 | 28 | 21 | 31 | 11 | 3 | 13 | 15 | 15 | 48 | 51 | 71 | 74 | 45 | 42 | 26 | 18 |
| Total | 14 | 20 | 46 | 50 | 59 | 23 | 12 | 22 | 21 | 33 | 81 | 107 | 124 | 144 | 83 | 76 | 50 | 35 |
| White: | 949 | 95.76% |
| Black: | 4 | 0.40% |
| Hispanic:* | 27 | 2.72% |
| Asian: | 9 | 0.91% |
| American Indian: | 0 | 0% |
| Hawaiian: | 0 | 0% |
| Other: | 2 | 0.20% |
| Total: | 991 | 100% |
| Gender | Count | % | Median Age |
|---|---|---|---|
| Males: | 477 | 47.70% | 59.6 years |
| Females: | 523 | 52.30% | 61.3 years |
| Total: | 1,000 | 100% | 60.8 years |
| Native, born in the United States: | 794 | 96.01% |
| Native, born in PR, Island Areas, or abroad: | 27 | 3.26% |
| Foreign born, naturalized U.S. citizen: | 6 | 0.73% |
| Foreign born, not a U.S. citizen: | 0 | 0.73% |
| Total Population: | 827 | 100% |
| Total Native Population: | 821 | 99.27% |
| Total Foreign-born Population: | 6 | 0.73% |
In 2024, the Median household income is $176,953, which is far above the national median ($78,538), is up $73,491 (71.0%) since 2011 and above its 2019 pre-pandemic level by $40,953. Family households earn a median of $201,250 versus $100,677 for nonfamily households (a difference of $100,573). By gender, male median income is $182,813 and female is $180,197, which is markedly greater than the national female median ($53,445), with a current gap of $2,616 that has narrowed from 2011 to 2024. The labor-force participation rate is 49.3%, which is much lower than the national rate (63.5%). The unemployment rate is 0.0%, which is markedly below the national rate (5.2%). The largest occupation group is Management (54.5%).
Explore More: Income Over Time Household Income Employment Status By Occupation
| Income Type | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median Household Income | $103,462 | $113,875 | $103,269 | $122,604 | $122,692 | $114,028 | $113,281 | $107,083 | $136,000 | $167,500 | $150,875 | $164,167 | $193,558 | $176,953 |
| Median Family Income | $119,038 | $127,768 | $124,750 | $135,833 | $139,076 | $140,236 | $144,813 | $155,417 | $230,987 | $250,001 | $246,181 | $250,001 | $250,001 | $201,250 |
| Median NonFamily Income | $64,167 | $56,250 | $48,194 | $54,063 | $53,250 | $52,692 | $51,848 | $56,528 | $51,705 | $79,219 | $77,188 | $89,583 | $95,260 | $100,677 |
| Median Male Income | $73,250 | $76,875 | $106,094 | $109,722 | $113,098 | $102,500 | $111,000 | $97,188 | $122,188 | $191,250 | $181,389 | $232,891 | $206,667 | $182,813 |
| Median Female Income | $44,625 | $52,500 | $53,409 | $57,237 | $56,652 | $56,696 | $61,458 | $58,558 | $0 | $127,969 | $86,563 | $169,583 | $152,361 | $180,197 |
| Employed: | 358 | 49.31% |
| Unemployed: | 0 | 0.00% |
| Not In Labor Force: | 368 | 50.69% |
| Total: | 726 | 100% |
| Management, business, science, and arts: | 195 | 54.47% |
| Service: | 40 | 11.17% |
| Sales and Office: | 85 | 23.74% |
| Natural resources, construction, and maintenance: | 21 | 5.87% |
| Production, transportation, and material moving: | 17 | 4.75% |
| Total Civilian Employed Population: | 358 | 100% |
In 2024, the median home value is $1,701,300, which is considerably higher than the national median ($303,400), is up $701,299 (70.13%) since 2011 and above its 2019 pre-pandemic level by $622,000. The median gross rent is $3,501, which is considerably higher than the national median ($1,348), is up $1,825 (108.89%) since 2011 and above its 2019 pre-pandemic level by $934. Of occupied housing, owners make up 93.02% (45.04% with a mortgage, 54.96% free-and-clear) and renters 6.98% - making this ZIP Code under national rental averages. The vacancy rate is 13.95%, which is considerably higher than the national rate (10.43%).
Explore More: Compare Home Value Home Value Over Time Rent & Over Time Housing Occupancy
| Group | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median Home Value | $1,000,001 | $1,000,001 | $1,000,001 | $1,000,001 | $987,500 | $941,600 | $988,800 | $949,200 | $1,079,300 | $1,140,000 | $1,192,900 | $1,475,000 | $1,612,700 | $1,701,300 |
| Less than $500: | 6 | 21.43% |
| $500 to $999: | 0 | 0.00% |
| $1,000 to $1,499: | 0 | 0.00% |
| $1,500 to $1,999: | 0 | 0.00% |
| $2,000 to $2,499: | 0 | 0.00% |
| $2,500 to $2,999: | 0 | 0.00% |
| $3,000 or more: | 22 | 78.57% |
| No Rent: | 0 | 0.00% |
| Total: | 28 | 100% |
| Group | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median Rent | $1,676 | $1,650 | $1,603 | $1,699 | $1,768 | $1,867 | $2,034 | $2,284 | $2,567 | $2,688 | $2,663 | $2,786 | $3,453 | $3,501 |
| Owner Occupied (with mortgage): | 168 | 41.90% |
| Owner Occupied (free and clear, no mortgage): | 205 | 51.12% |
| Renter Occupied: | 28 | 6.98% |
| Total Occupied Housing Units: | 401 | 100% |
| Occupied Housing Units: | 401 | 86.05% |
| Vacant Housing Units (not graphed): | 65 | 13.95% |
| Total Housing Units: | 466 | 100% |
| Single-Family Units: | 442 | 94.85% |
| Multi-Family Units: | 24 | 5.15% |
| Other Units: | 0 | 0.00% |
| Total Housing Units: | 466 | 100% |
In 2024, 68.80% of adults (25+) have a bachelor's degree or higher, which is far higher than the national rate (35.00%). High school or higher is 95.00%, which is far higher than the national rate (89.40%). The uninsured rate is 1.10%, which is far lower than the national rate (8.60%). Private coverage is 87.80%, which is well above the national rate (67.30%). The share of people in poverty is 5.20%, which is comparable to the national rate (8.70%), down 0.10 percentage points since 2011 and above its 2019 pre-pandemic level by 4.30 percentage points. Poverty has been broadly stable, which may reflect structural barriers or offsetting gains and setbacks. Among residents ages 3+, the largest enrollment group is elementary (50.00%). College enrollment is 7.58%, which is far lower than the national rate (26.70%), indicating the community may be more oriented toward vocational/trade or direct-to-workforce opportunities.
Explore More: Educational Attainment Health Insurance Poverty Over Time School Enrollment
| Less than 9th grade: | 12 | 1.73% |
| 9th to 12th grade, no diploma: | 23 | 3.31% |
| High school graduate (includes equivalency): | 42 | 6.04% |
| Some college, no degree: | 93 | 13.38% |
| Associate's degree: | 47 | 6.76% |
| Bachelor's degree: | 272 | 39.14% |
| Graduate or professional degree: | 206 | 29.64% |
| Total: | 695 | 100% |
| High school or higher: | 660 | 94.96% |
| Bachelor's degree or higher: | 478 | 68.78% |
| Private Insurance: | 726 | 66.30% |
| Public Insurance: | 360 | 32.88% |
| No Insurance: | 9 | 0.82% |
| Total: | 1,095 | 100% |
| Has Health Insurance: | 1,086 | 99.18% |
| Group | 2011 | 2102 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| % of People in Poverty | 4.4% | 3.3% | 2.9% | 3.4% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 1.2% | 4.2% | 4.4% | 4.3% | 5.2% |
Note: Counts of Families & People in poverty are not published at the ZIP Code level due to small sample sizes. Percentages shown are survey estimates from the American Community Survey (ACS). They may differ from official poverty statistics. The U.S. Census Bureau defines poverty status by comparing a family's or individual's total income with federal poverty thresholds that vary by family size and composition.
| Nursery School, Preschool: | 12 | 18.18% |
| Kindergarten: | 0 | 0.00% |
| Elementary school (grades 1-8): | 33 | 50.00% |
| High school (grades 9-12): | 16 | 24.24% |
| College or graduate school: | 5 | 7.58% |
| Total: | 66 | 100% |
| Early Childhood: | 12 | 18.18% |
| K-12 (Primary & Secondary School): | 49 | 74.24% |
ZIP Code 03854 supports both business and residential activity. According to the Business Census (2024), there are 19 business establishments, employing about 357 people with an annual payroll of $15,046,000.
| # Residential Mailboxes: | 0Source: USPS |
| # Business Mailboxes: | 0Source: USPS |
| Total Delivery Receptacles: | 577Source: USPS |
| Single Family Delivery Units: | 0Source: USPS |
| Multi Family Delivery Units: | 0Source: USPS |
| # of Businesses: | 19Source: CBP |
| 1st Quarter Payroll: | $2,692,000Source: CBP |
| Annual Payroll: | $15,046,000Source: CBP |
| # of Employees: | 357Source: CBP |
ZIP Code 03854 is located in Rockingham County, New Hampshire, within the Boston-Cambridge-Newton, MA-NH Metropolitan Statistical Area (CBSA 14460) and New Hampshire's 1st Congressional District. This Metro area has a population of 4,552,402 people, about 0.02% of whom live in ZIP Code 03854, and is subdivided into the Rockingham County-Strafford County, NH division. It covers 0.809 sq mi of land and a water area of 1.462 sq mi.
| CBSA Name: | Boston-Cambridge-Newton, MA-NHSource: Census |
| CBSA Number: | 14460Source: Census |
| CBSA Type: | MetroSource: Census |
| CBSA Division: | Rockingham County-Strafford County, NH (CBSA Div 40484)Source: Census |
| CBSA Population: | 4,552,402Source: Census |
| MSA: | Boston-Worcester-Lawrence, MA-NH-ME-CT CMSASource: Census |
| Land Area: | 0.809 sq miSource: Census |
| Water Area: | 1.462 sq miSource: Census |
| Congressional District: | 01Source: USPS |
| Congressional Land Area: | 2463.65 sq miSource: Census |
| PMSA: | Portsmouth-Rochester, NH-ME PMSASource: Census |
| Intro Date: | < 2004-10Source: ZIP-Codes.com |
| Place FIPS Code: | --Source: Census |
| Place Name: | --Source: Census |
ZIP Code 03854 is in the New Castle School District, which serves grades Kindergarten thru 12th. There are 1 public school(s) in this ZIP Code, and we have located 3 private school(s). It also has 6 colleges, universities or post secondary education institutions nearby which would be a short commute to.
Our sources include trusted federal and licensed data from the United States Postal Service, U.S. Census Bureau, U.S. Geological Survey, Centers for Medicare & Medicaid Services, and the National Center for Education Statistics, along with proprietary datasets created by ZIP-Codes.com. Data last updated on March 1, 2026.