Single Family for Sale: 350 Portsmouth Avenue, New Castle, NH 03854

3 beds
1 full, 2 three quarter, 1 half baths
3,238 sqft
$3,950,000
$3,950,000
350 Portsmouth Avenue, New Castle, NH 03854
3 beds
1 full, 2 three quarter, 1 half baths
3,238 sqft
$3,950,000
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Price:
$3,950,000
$250,000 - 09/29/2026

Type Single Family
Style Contemporary
Beds 3
Baths 1 full, 2 three quarter, 1 half baths
Square Feet 3,238 sqft
Lot Size 0.25 acres
Year Built 1977
Taxes Paid $15,636

City New Castle
County Rockingham
School District New Castle

MLS 5107161
Status Active
DOM 39 days
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.

Lot & Building Features

Appliances Double Oven, Electric Cooktop, Wall Oven, Dishwasher, Refrigerator
Features Interior Wood Fireplace, Cathedral Ceiling, 1 Fireplace, Kitchen Island, Primary BR w/ BA, Ceiling Fan, Natural Light, Dining Area
Utilities Cable
Construction Wood Siding, Wood Frame
Cooling Central AC
Heating Forced Air, Oil
Parking Description Auto Open, Direct Entry, Attached, Driveway
Sewer Public
Tax Year 2025
Taxes Paid $15,636
Water Public
Basement Description Climate Controlled, Daylight, Partially Finished, Walkout, Interior Stairs, Full
Foundation Poured Concrete
Lot Description Near Country Club, Near Golf Course, Near School(s), Near Shopping, Landscaped
Roof Asphalt Shingle
Features Exterior Sauna, Boat Mooring, Private Dock, Boat Slip/Dock, Hot Tub
Total Rooms 7
Garage Yes
Full Baths 1
3/4 Baths 2
Half Baths 1

Community and Schools

Elementary School Maude H. Trefethen School
Junior High School Rye Junior High School
Senior High School Portsmouth High School

Price History of 350 Portsmouth Avenue, New Castle, NH

Date Name Price Difference
09/29/2026 Price Adjustment $3,950,000 5.95%
08/28/2026 Listing Price $4,200,000 N/A
*Information provided by REWS for your reference only. The accuracy of this information cannot be verified and is not guaranteed.

Comparable Properties Sold Near By

Low
$2,900,000
$905 / sqft
Average
$3,016,667
$950 / sqft
High
$3,100,000
$1,014 / sqft

Address City Zip Beds Baths Price Sq. Ft. $/SQFT Sold Date
This Listing New Castle 03854 3 4.0 $3,950,000 3,238 $1,220 N/A
47 Tower Road Kittery 03904 3 3.0 $2,900,000 3,203 $905 10/07/2025
12 Ruth Street Portsmouth 03801 4 4.0 $3,050,000 3,263 $935 12/08/2025
17 Lavenger Lane New Castle 03854 4 4.0 $3,100,000 3,057 $1,014 03/17/2026

Map of 350 Portsmouth Avenue, New Castle, NH

Location Map Street View
Photo of Alyse Savage
Alyse Savage
Broker | Owner
Direct: 603-493-2026
Office
195 McGregor Street, Suite 325
Manchester, NH 03102
603-824-5794
Listed by Great Island Realty LLC, Janet Sylvester & Margaret Pesce 603-433-3350
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0.39584810126582%
6.75%
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Monthly Home Ins.
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350 Portsmouth Avenue (MLS #5107161) is a contemporary single family home located in New Castle, NH. This single family home is 3,238 sqft and on a lot of 10,890 sqft (or 0.25 acres) with 3 bedrooms, 4 baths and is 49 years old. This property was listed on 08/28/2026 and has been priced for sale at $3,950,000.

The 4 bedroom single family home at 17 Lavenger Lane in New Castle is nearby and sold for $3,100,000 on 03/17/2026. Another nearby 3 bedroom single family home, 47 Tower Road in Kittery sold for $2,900,000 on 10/07/2025.

Nearby zip codes are 03081, 03801 3828, 03801, 03840 and 03870. This property neighbors other cities such as Dover, Greenland, Newington, Portsmouth and Rye.

PrimeMLS

Listing Last updated . Some properties which appear for sale on this web site may subsequently have sold or may no longer be available. Walk Score map and data provided by Walk Score. Google map provided by Google. Bing map provided by Microsoft Corporation.

All information provided is deemed reliable but is not guaranteed and should be independently verified.

Listing information courtesy 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, non- commercial use and may not be used for any purpose other than to identify prospective properties consumers may be interested in purchasing. Data last updated 10/09/2026