350 Portsmouth AvenueNew Castle, NH 03854MLS Number 5107161

  • Price: $4,200,000
  • Est. Mortgage of $/month
  • 1 Day on Market
$
$
%
$/month over payments
Federal 30-year interest rate: 6.66% last updated on Aug 27, 2026
* All Figures are estimates. Check with your bank or proposed mortgage company for actual interest rates.
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350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854350 Portsmouth Avenue New Castle NH 03854
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  • 2Bedrooms
  • 0.25Acreage
  • 5Bathrooms
  • 1977Year Built

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Listed by Janet Sylvester of Great Island Realty LLC
Welcome to 350 Portsmouth Avenue, an exceptional waterfront residence offering a front row seat to one of the most captivating maritime settings on the New Hampshire Seacoast. With expansive water views of the Piscataqua River and Back Channel, this remarkable property captures everything that makes New Castle waterfront living so special. From magnificent ships and iconic Portsmouth tugboats to sailboats, fishing vessels and pleasure craft, the ever changing boat traffic provides a spectacular backdrop from morning until night. A private deep water dock makes this a dream for boating enthusiasts, offering direct access to Portsmouth Harbor, the Piscataqua River and the open Atlantic. Adding to the property's unique appeal is deeded access to the Back Channel, creating a wonderful launching point for kayaks and paddleboards. Designed to embrace this extraordinary setting, the home features multiple waterfront decks for entertaining, outdoor dining or simply watching the river come alive. A walk-out lower level extends the living space outdoors, while the hot tub and sauna create a private waterfront retreat to enjoy throughout the seasons. Enjoy all the amenities that make New Castle one of the Seacoast's most coveted communities, the nearby yacht clubs, Wentworth Marina, Wentworth by the Sea Country Club, Great Island Common, beaches and the historic charm of island living, all just minutes from downtown Portsmouth. And with New Castle's exceptionally low property taxes, this is a rare opportunity to combine an extraordinary waterfront lifestyle with one of New Hampshire's most desirable communities. Deep water boating out your front door. Kayaking and paddleboarding from your deeded Back Channel access. Incredible water views, spectacular boat traffic, waterfront decks, hot tub and sauna, all in the heart of New Castle. 350 Portsmouth Avenue isn't simply a waterfront home, it's a lifestyle defined by the water.

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More Info

Tax Information

  • Tax Year2025

Location

  • Building Number350
  • StreetPortsmouth Avenue
  • TownNew Castle
  • StateNH
  • Zip03854
  • CountyRockingham
  • DistrictNew Castle
  • Elementary SchoolMaude H. Trefethen School
  • Junior HighRye Junior High School
  • High SchoolPortsmouth High School
  • Map14
  • Flood Zone Y/NLand Only
  • Address350 Portsmouth Avenue

Interior

  • Interior FeaturesCathedral Ceiling, Ceiling Fan, Dining Area, Wood Fireplace,1 Fireplace, Kitchen Island, Primary BR w/ BA, Natural Light
  • FloorsCarpet, Tile
  • Stories2

Amenities

  • AmenitiesIrrigation Meter
  • PricePerSqFt1768.42

Water Body

  • Water Body NamePiscataqua River
  • Water Body TypeRiver
  • Waterfront100
  • Water AccessOwned
  • Water ViewYes
  • Water Access DetailsDeep Water Access, Dock Access

Parking

  • Parking Spaces2
  • GarageYes
  • Parking DescriptionAuto Open, Direct Entry, Driveway, Attached

Building

  • Year Built1977
  • Building ConstructionWood Frame, Wood Siding
  • ConstructionExisting
  • Property StyleContemporary
  • Bedrooms2
  • Bathroom5
  • Total Baths5
  • 3/4 Baths3
  • Half Bath1
  • Total Rooms7
  • Square Feet3,238
  • APX Unfin Below Grade943
  • BasementClimate Controlled, Daylight, Full, Interior Stairs, Partially Finished, Walkout
  • FoundationPoured Concrete

Exterior

  • Exterior FeaturesBoat Mooring, Boat Slip/Dock, Hot Tub, Private Dock, Sauna
  • Exterior ColorGray
  • RoofAsphalt Shingle

Rooms

  • Full Bath1

Basic Information

  • MLS Number5107161
  • MLS StatusActive
  • Virtual TourView Tour
  • StatusACT
  • Property TypeSingle Family
  • List Price$4,200,000
  • Listing Agent NameJanet Sylvester
  • Broker NameGreat Island Realty LLC

Property

  • Acreage0.25
  • Lot DescriptionLandscaped, Near Country Club, Near Golf Course, Near Shopping, Near School(s)
  • AreaNH-Rockingham
  • Lot10
  • DrivewayPaved
  • RoadsPaved, Public Maintained Road
  • Road Frontage100

Utilities

  • Heat SystemOil, Forced Air
  • WaterPublic
  • SewerPublic
  • Electric200+ Amp Service
  • UtilitiesCable

Other

  • SeasonalNo
  • Page362
  • Date Listed08/28/2026
  • View Count1
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