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Single Family ResidenceResidential
$1,457,023$750 / ft²
TopHap EstimateOur estimate of what this home would sell for today, based on nearby sales, the home's size and features, and local price trends. It is a starting point, not an appraisal.· confidence 89How well the pricing models agreed with each other on this home. Higher means the estimate rests on stronger, more consistent data.· as of Oct 21, 2026

351 UNION ST

PORTSMOUTH, NH 03801
3
Beds
2
Baths
1,942 ft²
Living AreaTotal finished area of the structures, from county records. Some counties include shared space like hallways or a building gym, so it may not match a listing.
0.26 ac
Lot SizeThe size of the land the home sits on, from county records.
1877
Year BuiltThe year the home was originally built, according to county records.
2
StoriesHow many floors the home has above ground.
9
RoomsThe total room count in county records. Counties differ on which rooms they count, so compare it loosely.

Valuation

$1.5M
$1.3M low$1.6M high

Tax & Assessment

Property TaxThe property tax billed for this tax year. It usually pays for schools, roads, and local services.$13,413 (2025)
Assessed ValueThe value the county assigns to this home to calculate property tax. It is often lower than what the home would sell for.$1,165,300 (2025)
Assessed LandThe share of the county's assessed value that comes from the land itself, not the buildings.$686,100
Assessed ImprovementsThe share of the county's assessed value that comes from the buildings and other structures on the land.$479,200
Assessor Market ValueThe county assessor's own opinion of market value. It is separate from our estimate and updates on the county's schedule.$1,157,955

Property Facts

Property TypeThe broad category the county puts this property in, such as residential or commercial.Single Family Residence
StyleThe architectural style of the home, such as ranch or colonial.Conventional
CountyROCKINGHAM
Lot (acres)The size of the land the home sits on, from county records.0.26
RoofThe main material covering the roof, such as asphalt shingle or tile.Asphalt
HeatingThe type of heating system in the home.Hot Water
FireplaceWhether the home has a fireplace, and what kind.Yes
PoolWhether the property has a pool, and what kind, such as in-ground.No
FeaturesExtra features found in county records. Records are not complete everywhere, so a missing feature does not always mean the home lacks it.Deck

Assigned SchoolsThe public schools this address is zoned for. Boundaries change, so confirm with the district before you count on it.

M
Portsmouth Middle SchoolA
Middle · Grades 6–8 · 0.4 mi
E
Little Harbour Elementary SchoolA+
Elementary · Grades KG–5 · 0.6 mi
H
Portsmouth High SchoolA
High · Grades 9–12 · 0.7 mi

District: Portsmouth School District

Neighborhood · ZIP 03801These are comparison scores, not percentages. 100 equals the national average, so 150 means about 50% above average.

CrimeLocal crime compared with the rest of the country, where 100 is average. It reflects things like population density, income, and how crime gets reported.138
Air pollutionOverall air pollution compared with the rest of the country, where 100 is average. Lower is cleaner.104
EarthquakeEarthquake risk and likely building damage compared with the rest of the country, where 100 is average. Scores can run far above 100.98

Index scale: 100 = US average (tick). Lower is better.

Homes occupiedThe share of homes here that someone lives in. The rest sit empty, including vacation and for-sale homes.95%
Bachelor's or higherThe share of adults 25 and older whose highest degree is a bachelor's degree.41%
Poverty rateThe share of people whose household income falls below the federal poverty line, which varies by family size.5.0%
UnemploymentThe share of men 16 and older who are out of work and actively looking. Only men are counted in this figure.0.9%
PopulationHow many people live in this area.24,014
DensityPeople per square mile. Higher numbers mean a more crowded, urban area.808 / mi²
Median incomeThe middle household income here — half of households earn more, half earn less.$107,161
Average incomeThe average household income. It runs higher than the median when a few high earners pull it up.$136,932
Average tempThe average temperature here across a full year.48°F
Annual precipHow much rain and melted snow falls here in a typical year.47 in
SunshineThe share of daylight hours that get direct sun in a typical year, counting cloud cover.54%

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Data by ATTOM. Valuations are automated estimates, not appraisals. Photos from Google Street View and may not depict the current property state.

How this home compares

351 Union St measured against every home in its neighborhood, its ZIP code and its county, using county assessor records refreshed nightly. A home can stand out in one of those areas and look ordinary in another, because each one holds a different mix of homes.

  • Worth more than 96% of homes in Rockingham County
  • Costs more per square foot than 95% of homes in Rockingham County
  • Bigger than 69% of homes in Portsmouth 03801
  • Has a bigger lot than 88% of homes in Wibird Area
  • Older than 96% of homes in Rockingham County

What homes are worth in Portsmouth 03801

Each bar is how many homes fall in that price range. The marker is this home.

This home
$289K$3M

This home is worth more than 83% of homes in Portsmouth 03801.

How it measures up in Portsmouth 03801

The dot is this home. The mark in the middle is the typical home in Portsmouth 03801.

Estimated value$1,457,023
CheaperTypical $828,279Pricier

Pricier than 83% of homes nearby

Price per ft²$750
CheaperTypical $577Pricier

Pricier than 76% of homes nearby

Living area1,942 ft²
SmallerTypical 1,521 ft²Bigger

Bigger than 69% of homes nearby

Lot size0.26 ac
SmallerTypical 0.22 acBigger

Bigger than 60% of homes nearby

Year built1877
OlderTypical 1962Newer

Newer than 10% of homes nearby

How 351 Union St ranks against every home in each area.
MeasureThis homeWibird AreaPortsmouth 03801Rockingham County
Estimated valuepricier than$1,457,02356% of homes83% of homes96% of homes
Price per ft²pricier than$75058% of homes76% of homes95% of homes
Living areabigger than1,942 ft²50% of homes69% of homes57% of homes
Lot sizebigger than0.26 ac88% of homes60% of homes20% of homes
Year builtnewer than187710% of homes10% of homes4% of homes

About 351 Union St

How much is 351 Union St, Portsmouth, NH worth?

The TopHap Estimate for 351 Union St, Portsmouth, NH is $1,457,023 as of Oct 21, 2026. The likely range is $1,289,530 to $1,624,516. The estimate is modelled from recorded sales, assessments and the property's own characteristics — it is not an appraisal.

When did 351 Union St, Portsmouth, NH last sell?

351 Union St, Portsmouth, NH last sold on Jan 1, 1900, according to the county's recorded deed.

How big is 351 Union St, Portsmouth, NH?

351 Union St, Portsmouth, NH has 3 bedrooms, 2 bathrooms, 1,942 square feet of living space and a 0.26-acre lot.

When was 351 Union St, Portsmouth, NH built?

351 Union St, Portsmouth, NH was built in 1877, making it 149 years old. It is a conventional home. The building has 2 stories.

What schools serve 351 Union St, Portsmouth, NH?

351 Union St, Portsmouth, NH is assigned to Portsmouth Middle School (middle), rated A; Little Harbour Elementary School (elementary), rated A+; Portsmouth High School (high), rated A. All sit in Portsmouth School District. Attendance boundaries change — confirm with the district before relying on an assignment.

How does 351 Union St, Portsmouth, NH compare to other homes in Portsmouth 03801?

Among the 8,130 homes in Portsmouth 03801, it is worth more than 83% of them ($1,457,023 against a typical $828,279), its price per square foot is higher than 76% of them ($750 against a typical $577), it is bigger than 69% of them (1,942 ft² against a typical 1,521 ft²), its lot is bigger than 60% of them (0.26 ac against a typical 0.22 ac) and it is newer than 10% of them (1877 against a typical 1962). Measured against all of Rockingham County, it is worth more than 96% of homes there. These shares are recounted nightly from the full county assessor record for each area, not from active listings.

What are the property taxes on 351 Union St, Portsmouth, NH?

The 2025 property tax bill for 351 Union St, Portsmouth, NH was $13,413. The county assessed it at $1,165,300.

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