.52 Acre Buildable Lot with Existing Cottage — North Mianus
Nestled at the end of a private road in the desirable North Mianus neighborhood, this .52-acre property offers a unique combination of privacy, potential, and flexibility. The lot is fully entitled with plans to build a 4,200 sq. ft. custom home, making it ideal for builders, investors, or end-users looking to create their dream residence.
In addition to the new-construction opportunity, the property includes an existing 1-bedroom, 1-bathroom cottage that is grandfathered in—perfect for rental income, a guest house, or an in-law suite while the main home is being built.
This is a rare offering in one of Greenwich's most sought-after areas, within the North Mianus Elementary and Eastern Middle School districts,
Lot/land
$1,575,000
9 Walnut St, Cos Cob, CT 06807
3beds
0.52Acres
Land
Built in 1970
0.52 Acres Lot
$-- Zestimate®
$1,063/sqft
$-- HOA
What's special
Private road
- 45 days |
- 848 |
- 29 |
Zillow last checked: 8 hours ago
Listing updated: December 10, 2025 at 12:16pm
Listed by:
Peter Janis 203-249-1013,
BHHS New England Properties
Source: Greenwich MLS, Inc.,MLS#: 123887
Facts & features
Interior
Bedrooms & bathrooms
- Bedrooms: 3
- Bathrooms: 1
- Full bathrooms: 1
Heating
- Natural Gas, Hot Water
Cooling
- None
Interior area
- Total structure area: 1,482
- Total interior livable area: 1,482 sqft
Property
Lot
- Size: 0.52 Acres
- Features: Level
Details
- Additional structures: Guest House
- Parcel number: 082718/S
- Zoning: R-12
Utilities & green energy
- Water: Public
Community & HOA
Location
- Region: Cos Cob
Financial & listing details
- Price per square foot: $1,063/sqft
- Tax assessed value: $714,140
- Annual tax amount: $8,825
- Date on market: 10/27/2025
Estimated market value
Not available
Estimated sales range
Not available
$4,887/mo
Price history
Price history
| Date | Event | Price |
|---|---|---|
| 10/27/2025 | Listed for sale | $1,575,000+54.4%$1,063/sqft |
Source:  Greenwich MLS, Inc. #123887 Report a problem | ||
| 7/10/2025 | Sold | $1,020,000-11.3%$688/sqft |
Source:  Smart MLS #24073498 Report a problem | ||
| 3/6/2025 | Pending sale | $1,150,000$776/sqft |
Source: Smart MLS #24073498 Report a problem | ||
| 2/17/2025 | Contingent | $1,150,000$776/sqft |
Source:  Berkshire Hathaway HomeServices New England Properties #122061 Report a problem | ||
| 2/17/2025 | Pending sale | $1,150,000$776/sqft |
Source: Greenwich MLS, Inc. #122061 Report a problem | ||
Public tax history
Public tax history
| Year | Property taxes | Tax assessment |
|---|---|---|
| 2025 | $8,826 +3.5% | $714,140 |
| 2024 | $8,524 +2.6% | $714,140 |
| 2023 | $8,310 +0.9% | $714,140 |
Find assessor info on the county website
BuyAbility℠ payment
Estimated monthly payment
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Neighborhood: Cos Cob
Nearby schools
GreatSchools rating
- 9/10North Mianus SchoolGrades: K-5Distance: 0.8 mi
- 9/10Eastern Middle SchoolGrades: 6-8Distance: 2.4 mi
- 10/10Greenwich High SchoolGrades: 9-12Distance: 2.7 mi
Schools provided by the listing agent
- Elementary: North Mianus
- Middle: Eastern Middle
Source: Greenwich MLS, Inc.. This data may not be complete. We recommend contacting the local school district to confirm school assignments for this home.
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