How old are the homes in Thornwood, NY?

Name: Age of homes in Thornwood, NY, 2020–2024
Creator: US Census Bureau
License: https://www.census.gov/data/developers/about/terms-of-service.html

84.3% (±15.6 points) of the homes in Thornwood, NY were built before 1980 (2020–2024 American Community Survey).

14.2% were built before 1940.

4.8% were built in 2010 or later.

Figures last updated on November 12, 2026.

Built before 1980: 84.3% (±15.6 points)
Built before 1940: 14.2%
Built 2010 or later: 4.8%

When the homes in Thornwood were built

Housing units by year structure built, 2020–2024
Year built	Thornwood	Westchester County	New York	United States
2020 or later	0.0% (±2.8 points)	1.0%	0.8%	2.0%
2010 to 2019	4.8% (±4.4 points)	4.2%	5.3%	9.4%
2000 to 2009	3.2% (±3.1 points)	5.4%	6.4%	13.6%
1990 to 1999	5.8% (±4.4 points)	5.0%	5.9%	12.4%
1980 to 1989	1.9% (±1.8 points)	8.4%	7.7%	12.9%
1970 to 1979	10.3% (±4.9 points)	9.9%	9.8%	14.2%
1960 to 1969	27.4% (±10.4 points)	14.0%	12.1%	9.9%
1950 to 1959	30.2% (±8.0 points)	17.6%	14.1%	9.5%
1940 to 1949	2.2% (±2.2 points)	7.1%	7.6%	4.4%
1939 or earlier	14.2% (±6.4 points)	27.5%	30.3%	11.7%

In Thornwood, the share of homes built before 1980 is not measurably different from Westchester County (76.1%).

It is not measurably different from New York (73.9%).

It is higher than the national figure (49.7%).

In Westchester County, Thornwood ranks 8 of 24 places with a published estimate, from highest to lowest share of homes built before 1980.

Statewide, it ranks 99 of 414.

Rankings use the estimates alone; where margins of error overlap, neighboring ranks may not truly differ.

Why the age of a home matters: lead-based paint

Federal law treats housing built before 1978 as likely to contain lead-based paint.

Before a lease or sale of most pre-1978 housing, the landlord or seller must disclose any known lead-based paint and hazards and give the tenant or buyer the EPA pamphlet (42 U.S.C. § 4852d; 40 CFR part 745, subpart F; 24 CFR part 35, subpart A).

A contractor paid to renovate, repair or paint a pre-1978 home must be a certified firm, use a certified renovator and follow lead-safe work practices under the Renovation, Repair and Painting Rule (40 CFR part 745, subpart E) whenever the job disturbs more than 6 square feet of painted surface in a room or more than 20 square feet outside; window replacement and demolition always count (40 CFR 745.83).

Certification comes from EPA, or from the state where EPA has authorized the state to run the program.

The Census Bureau groups construction by decade, so the share built before 1978 lies between the share built before 1970 (74.0%) and the share built before 1980 (84.3%).

Homes built before 1980 in places near Thornwood

Nearest places with a published estimate, compared with Thornwood
Place	Distance	Homes built before 1980	Compared with this place
Thornwood	—	84.3% (±15.6 points)	—
Village of Pleasantville	1.1 mi	82.6% (±11.3 points)	Not measurably different
Hawthorne	1.4 mi	87.6% (±15.2 points)	Not measurably different
Chappaqua	2.7 mi	63.6% (±21.3 points)	Not measurably different
Valhalla	2.8 mi	85.4% (±16.7 points)	Not measurably different
Armonk	3.3 mi	43.2% (±11.0 points)	Lower
Village of Briarcliff Manor	3.9 mi	57.4% (±8.0 points)	Lower
Town of New Castle	4.4 mi	68.5% (±9.0 points)	Not measurably different
Town of Ossining	4.8 mi	67.8% (±5.1 points)	Lower

Nearby places with a measurably lower figure: Armonk, NY (43.2%), Village of Briarcliff Manor, NY (57.4%), Town of Ossining, NY (67.8%).

Distance is measured in a straight line between the Census Bureau’s internal points for each place.

Homes built before 1980 across Westchester County, place by place

Rank	Place	Homes built before 1980
2	Katonah	90.0% (±26.4 points)
3	Eastchester (community)	89.3% (±6.3 points)
4	Montrose	88.5% (±19.3 points)
5	Hawthorne	87.6% (±15.2 points)
6	Hartsdale	86.5% (±14.9 points)
7	Valhalla	85.4% (±16.7 points)
8	Thornwood	84.3% (±15.6 points)
9	Greenville	83.6% (±11.1 points)
10	Bedford (community)	82.4% (±20.8 points)
11	Yorktown Heights	82.3% (±30.3 points)
12	Shenorock	80.0% (±25.0 points)
13	Bedford Hills	78.4% (±21.0 points)
14	Jefferson Valley-Yorktown	77.3% (±8.6 points)

Showing 13 of 24 places in Westchester County, ranked from highest to lowest.

Thornwood is a census-designated place: an unincorporated community the Census Bureau draws for statistics, with no municipal government of its own.

It lies inside the Town of Mount Pleasant, whose figures include it.

Survey years: 2020–2024 (American Community Survey 5-year estimates).

Margins of error are at the 90% confidence level.

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Questions about Thornwood

How old are most homes in Thornwood?

84.3% of homes in Thornwood, NY were built before 1980 (2020–2024 American Community Survey).

Do homes in Thornwood need a lead paint disclosure?

A home built before 1978 does, before it is rented or sold, unless an exemption applies (42 U.S.C. § 4852d); between 74.0% and 84.3% of homes in Thornwood were built before then.

Does a contractor need lead certification to work on older homes in Thornwood?

Yes, when the job disturbs more than 6 square feet of paint in a room or 20 square feet outside, or replaces a window: the firm must be certified and a certified renovator must direct the work under the Renovation, Repair and Painting Rule (40 CFR part 745, subpart E).

Sources

Selected Housing Characteristics (DP04), 2020–2024 ACS 5-year estimates — Thornwood CDP, New York

To check these figures in the Census Bureau’s own API, request the variables below from the 2024 ACS 5-year data profile (acs/acs5/profile) for Thornwood CDP, New York (place:73715, in state:36).

Each estimate (E or PE) has a margin of error beside it (M or PM).

The API needs a free key.

Request a Census API key.

DP04_0017PE, DP04_0017PM, DP04_0018PE, DP04_0018PM, DP04_0019PE, DP04_0019PM, DP04_0020PE, DP04_0020PM, DP04_0021PE, DP04_0021PM, DP04_0022PE, DP04_0022PM, DP04_0023PE, DP04_0023PM, DP04_0024PE, DP04_0024PM, DP04_0025PE, DP04_0025PM, DP04_0026PE, DP04_0026PM

This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.

Figures are published by the US Census Bureau, HUD, the Bureau of Labor Statistics and the FBI; Seayora reproduces them and does not adjust them, except where a sentence says it compares dollar figures after inflation. They describe the whole place, not any one building or street, and are not an appraisal, a rent determination, a tax bill, a safety rating or legal advice.