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$4,200,000
14 Days On Site

350 Portsmouth Avenue
New Castle, NH 03854

For Sale|Single Family Residence|Active
3
Beds
5
Total Baths
1
Full Bath
4
Partial Baths
3,238
SqFt
$1,297
/SqFt
1977
Built
County:
Rockingham
Listing courtesy of Janet Sylvester of Great Island Realty LLC
Call Now: (207) 255-7659
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(207) 255-7659
350 Portsmouth Avenue350 Portsmouth Avenue350 Portsmouth Avenue350 Portsmouth Avenue
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Mortgage Calculator

Monthly Payment (Est.)

$19,162
Calculator powered by Showcase IDX, a Constellation1 Company. Copyright ©2026 Information is deemed reliable but not guaranteed.

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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Listing Snapshot
Price 
$4,200,000
Days On Site 
14 Days
Bedrooms 
3
Inside Area (SqFt) 
3,238 sqft
Total Baths 
5
Full Baths 
1
Partial Baths 
4
Lot Size 
0.25 Acres
Year Built 
1977
MLS® Number 
5107161
Status 
Active
Property Tax 
$15,636
HOA/Condo/Coop Fees 
N/A
Sq Ft Source 
N/A
Friends & Family
Recent Activity
a week agoListing updated with changes from the MLS®
2 weeks agoStatus changed to Active
2 weeks agoListing first seen on site
General Features
Acres 
0.25
Garage 
Yes
Garage Spaces 
2
Number Of Stories 
2
Parking 
PavedDrivewayAttached
Parking Spaces 
2
Property Sub Type 
Single Family Residence
Sewer 
Public Sewer
SqFt Above 
2375
SqFt Below 
863
SqFt Total 
4181
Style 
Contemporary
Utilities 
Cable Available
Water Source 
Public
Zoning 
RD RE
Interior Features
Appliances 
DishwasherRefrigeratorElectric CooktopDouble Oven
Basement 
FinishedFullPartially FinishedWalk-Out AccessDaylight
Cooling 
Central Air
Electric 
200+ Amp Service
Flooring 
CarpetTile
Heating 
OilForced Air
Interior 
Kitchen Island
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Exterior Features
Construction Details 
Wood Siding
Exterior 
Dock
Lot Features 
LandscapedNear Golf CourseWaterfront
Roof 
Shingle
View 
Water
Waterfront 
Yes
Waterfront Features 
River Front
Waterview 
Water
Community Features
School District 
New Castle
Schools
School District
New Castle
Elementary School
Maude H. Trefethen School
Middle School
Rye Junior High School
High School
Portsmouth High School
Listing courtesy of Janet Sylvester of Great Island Realty LLC



Copyright 2026, PrimeMLS, Inc. All rights reserved. This information is deemed reliable, but not guaranteed. The data relating to real estate displayed on this display comes in part from the IDX Program of PrimeMLS. The information being provided is for consumers’ personal, noncommercial use and may not be used for any purpose other than to identify prospective properties consumers may be interested in purchasing.
Last checked: 2026-09-11 11:25 PM UTC
Neighborhood & Commute
Source: Walkscore
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