- $2.65M MEDIAN SALE PRICE
- $950–$1,100+ PRICE PER SQ FT
- Single Digits ACTIVE INVENTORY
- Lowest PROPERTY TAX RATE IN NH
Seacoast New Hampshire
New Castle, NH real estate
New Castle is an island town of roughly 1,000 residents connected by causeway to Portsmouth, with Wentworth by the Sea and some of the highest-priced homes in New Hampshire. Only a handful of homes sell in a typical year.
Market snapshot
Updated November 2026
New Castle · Last 90 days of closed sales
- Median sale price Last 90 days
- $2,650,000
- Avg. days on market List to accepted offer
- 62 days
- Active listings Single-family and condo
- 6
- Sale-to-list ratio Sale price vs. last list
- 95.9%
- Homes sold Last 90 days
- 5
Median price, 12 months+13.6% YoY
Nick's read. New Castle closed 5 homes in the last 90 days at a median of $2,650,000. Well-priced listings are going under agreement in about 62 days, and a 95.9% sale-to-list ratio says buyers are still paying close to ask. Days on market crept up from the spring, which is normal for the fall.
Sample figures shown for layout; replace with the current month before publishing. All New Castle sales on Zillow ↗
Neighborhoods
Where people buy in New Castle
- 01Wentworth by the SeaHistoric hotel, marina and nearby residences
- 02Main Street villageAntique capes and colonials in the historic center
- 03Great Island CommonWaterfront park and the homes around it
Recent sales
Closed transactions where Nick represented the buyer, the seller, or both
-
98 Beach Hill Road
$6,495,000
Sold · Featured sale
Carey & Giampa Realtors
-
Wentworth Rd
$2,065,000
Sample row: replace with a real sale
-
Main St
$2,785,000
Sample row: replace with a real sale
Town guide
Living in New Castle
New Castle is the smallest town in New Hampshire and the only one located entirely on a collection of islands. At just 0.8 square miles of land, connected to Portsmouth and Rye by three scenic bridges, it offers something that simply cannot be replicated anywhere else on the Seacoast: geographic scarcity. There are only so many homes on Great Island, and there will never be more.
That scarcity — combined with historically low property taxes, direct Atlantic frontage, deep-water dock access, and a community that includes some of New England's most significant historic properties — makes New Castle consistently the most expensive ZIP code in New Hampshire. For buyers, the challenge isn't finding a home you want to live in. It's finding one that's available. For sellers, the fundamentals couldn't be stronger.
A Legacy Dating Back to 1623
Long before New Castle became the Seacoast's premier luxury address, it was known as "Great Island" — settled in 1623 and officially incorporated in 1693. The town's role in American history is extraordinary for a community of its size.
Fort Constitution, originally built as Fort William and Mary, was the site of one of the first overt acts of the American Revolution in December 1774, when local colonists raided the fort and seized British gunpowder — months before the battles of Lexington and Concord. Fort Stark, a later military fortification on the island's eastern shore, now serves as a historic site with breathtaking views of the Atlantic and the Isles of Shoals.
The Wentworth by the Sea, built in 1874, is arguably the most historically significant hotel in New Hampshire. It hosted the signing of the Treaty of Portsmouth in 1905, which ended the Russo-Japanese War and earned President Theodore Roosevelt the Nobel Peace Prize. Today, the fully restored Grand Dame operates as a Marriott luxury resort and remains the architectural centerpiece of the island.
New Castle, NH Real Estate Market Data (2026)
New Castle's market operates on different rules than the rest of the Seacoast. Inventory is measured in single digits, turnover is slow, and many of the highest-value transactions happen privately — off-market, through agent networks and direct relationships. This is not a market where you browse Zillow and schedule a showing. It's a market where access, timing, and trusted local representation define outcomes.
The combination of a $2.65 million median sale price and historically the lowest property tax rate in New Hampshire creates an unusually compelling value proposition for high-net-worth buyers — particularly those relocating from Massachusetts, Connecticut, or New York, where the tax savings alone can be transformational. New Castle's geographic constraint means this isn't a market that will see meaningful new supply. The island is built out.
Top Real Estate Sales in New Castle, NH
New Castle's highest-value transactions often happen privately, but public records tell a remarkable story. Luxury estates in the Wentworth by the Sea vicinity and along Little Harbor Road regularly command prices exceeding $5,500,000 — placing New Castle alongside the most exclusive coastal markets in New England.
A historic residence at 18 Becker Lane set a Seacoast benchmark with a sale price of $5,937,500. More recently, the iconic 1669-built estate at 24 Salamander Lane sold for over $5.6 million — a striking confirmation that even the town's oldest antique homes, when properly maintained and positioned, are among the most valuable residential properties in the northeastern United States.
What Is Your Home Worth in New Castle, NH?
If you own property on Great Island, your home value is likely at an all-time high. New Castle's geographic constraint — 0.8 square miles of land with no room to build — creates a supply dynamic that insulates property values in ways that few markets in the country can match.
But accurately pricing a New Castle home requires far more than comparable sales data, because there are rarely true comparables. Each property on the island is essentially unique. When I evaluate a New Castle property, I focus on:
Waterfront Frontage & Dock Access
Deep-water dock potential, direct Atlantic views, and protected harbor frontage are the primary value drivers on Great Island. The distinction between "water view" and "water access" can represent a seven-figure difference in pricing.
Historic Pedigree
New Castle contains some of the oldest residential structures in the United States. Properties with documented colonial provenance — original timbers, period fireplaces, hand-forged hardware — combined with thoughtful modern updates command extraordinary premiums from preservation-minded buyers.
Mooring & Maritime Rights
Mooring rights, dock permits, and direct launch access are among the most valuable — and most overlooked — assets attached to New Castle properties. These rights don't appear in automated estimates but can significantly impact market value.
Proximity To The Common
Walking distance to Great Island Common, Sandy Beach, and the Wentworth Marina defines the lifestyle center of New Castle. Homes in this radius benefit from both convenience and the island's most iconic views.
Tax Advantage Positioning
New Castle's historically low property tax rate is a significant selling point for out-of-state buyers. Positioning your property's tax advantage alongside its lifestyle and location can meaningfully expand your buyer pool and accelerate your sale.
Online algorithms struggle with New Castle more than any other market on the Seacoast — because the inputs they rely on (recent comps, lot size, square footage) fail to capture what actually drives value on a one-of-a-kind island. Contact me for a confidential, professional valuation that accounts for what makes your property irreplaceable.
Things to Do in New Castle, NH
Living on Great Island means having some of the Seacoast's most extraordinary attractions in your own backyard — and downtown Portsmouth just across the bridge. The lifestyle is quiet, private, and deeply connected to the water.
Great Island Common
A 31-acre seaside park featuring Sandy Beach, picnic grounds, and panoramic views of Portsmouth Harbor, the lighthouses, and the open Atlantic. The social and recreational heart of the island.
Fort Constitution & Fort Stark
Two historic military fortifications with stunning coastal access. Fort Constitution marks one of the first acts of the American Revolution; Fort Stark offers trails, tide pools, and some of the most dramatic ocean views on the NH coast.
Wentworth By The Sea Hotel & Spa
World-class dining, a full-service spa, and luxury accommodations in a meticulously restored 1874 grand hotel. A landmark that defines New Castle's identity and lifestyle.
Wentworth By The Sea Country Club
Home to the only oceanfront golf course in New Hampshire. A private club with a storied history and views that rival any course in New England.
Portsmouth Harbor Lighthouse
An iconic 48-foot tower on the island's northern tip, offering seasonal tours and a window into New Castle's centuries-long maritime heritage.
Why Work with a Top Realtor in New Castle, NH?
New Castle's market doesn't operate like a typical residential market. Many of the best homes on the island never appear on the MLS — they're sold through private networks, direct outreach, and agent-to-agent relationships built over years of working in this specific community. Access is the first barrier, and it's one that only a locally connected agent can solve.
Beyond access, New Castle transactions involve specific complexities that require deep expertise: historic district regulations, coastal flood zones, mooring and dock permitting, tidal boundary considerations, and marketing to a buyer pool that is often national or international in scope.
Whether you're considering selling a waterfront estate, exploring an off-market opportunity, or looking for a coastal cottage on Great Island, I bring over a decade of Seacoast experience, the relationships that open doors in this exclusive market, and the strategic marketing reach to present New Castle properties to the right audience — locally and globally.
Questions
Buying and selling in New Castle
$2,650,000, based on closed sales over the last 90 days, updated November 2026. 5 homes sold in that window and 6 are active today.
About 62 days from listing to accepted offer on average. Homes are closing at 95.9% of their last list price, so pricing correctly on day one still matters more than anything else.
Automated estimates struggle in New Castle because of the price spread between neighborhoods and the small number of annual sales. Nick prepares a confidential valuation from comparable closed sales, absorption rate and your property's specifics, at no cost.