Cos Cob vs Old Greenwich

A side-by-side comparison of Cos Cob and Old Greenwich: population, income, housing, and more.

Cos Cob and Old Greenwich are places in Connecticut. This page compares them across population, income, housing, education, commuting, and how each has changed since 2019.

Cos Cob has the higher population (7,354 vs 6,904 in Old Greenwich). Old Greenwich has the higher median household income ($250,001 vs $176,602 in Cos Cob). Old Greenwich has the higher median home value ($1,668,200 vs $1,149,500 in Cos Cob).

Population, income & housing

	Cos Cob	Old Greenwich
Population	7,354	6,904
Median age	39.3 yrs	40.5 yrs
Median household income	$176,602	$250,001
Median home value	$1,149,500	$1,668,200
Median gross rent	$2,574	$3,501
Housing units	2,711	2,482
Homeownership rate	65.4%	85.4%
Bachelor's degree or higher	70.3%	84.3%
Unemployment rate	6.1%	4.7%

Trends (ACS 5-year, 2019–2023)

	Cos Cob	Old Greenwich
Population	6,990 → 7,354 (+5.2%)	6,844 → 6,904 (+0.9%)
Median household income	$149,375 → $176,602 (+18.2%)	$222,794 → $250,001 (+12.2%)
Median home value	$1,055,400 → $1,149,500 (+8.9%)	$1,561,200 → $1,668,200 (+6.9%)
Median gross rent	$1,979 → $2,574 (+30.1%)	$2,127 → $3,501 (+64.6%)

Cos Cob

Population

6,9907,354

Median household income

$149,375$176,602

Median home value

$1,055,400$1,149,500

Median gross rent

$1,979$2,574

Old Greenwich

Population

6,8446,904

Median household income

$222,794$250,001

Median home value

$1,561,200$1,668,200

Median gross rent

$2,127$3,501

Age & race/ethnicity

Age distribution (share)

	Cos Cob	Old Greenwich
Under 5	9.0%	8.1%
5 to 17	20.0%	25.3%
18 to 24	6.1%	5.8%
25 to 34	8.6%	2.2%
35 to 44	15.2%	17.6%
45 to 54	13.3%	12.5%
55 to 64	13.9%	14.1%
65 to 74	8.9%	7.5%
75 and over	4.9%	6.9%

Race & ethnicity (share)

	Cos Cob	Old Greenwich
White (non-Hispanic)	67.2%	77.5%
Black or African American	2.9%	0.5%
American Indian & Alaska Native	0.4%	0.0%
Asian	5.4%	8.4%
Native Hawaiian & Pacific Islander	0.0%	0.0%
Some other race	0.8%	0.2%
Two or more races	9.2%	5.8%
Hispanic or Latino	14.2%	7.6%

Educational attainment (age 25+)

Share of adults 25+

	Cos Cob	Old Greenwich
No high school diploma	3.9%	1.2%
High school graduate	15.0%	6.6%
Some college or associate's	10.8%	7.9%
Bachelor's degree	33.4%	43.7%
Graduate or professional degree	36.9%	40.6%

Commute to work

How workers get to work (share)

	Cos Cob	Old Greenwich
Drove alone	54.8%	38.3%
Carpooled	4.9%	2.0%
Public transit	9.0%	19.8%
Walked	1.9%	1.1%
Bicycle	0.0%	0.3%
Worked from home	27.9%	38.0%
Other means	1.5%	0.4%

Housing

Units in structure (share)

	Cos Cob	Old Greenwich
1-unit, detached	58.2%	81.3%
1-unit, attached	11.8%	3.6%
2 to 4 units	23.5%	2.6%
5 to 19 units	5.1%	2.9%
20 or more units	1.1%	9.6%
Mobile home & other	0.2%	0.0%

Poverty & households

	Cos Cob	Old Greenwich
Poverty rate	5.5%	3.3%
Average household size	2.78	2.98
Mean commute (minutes)	29	37
Median year structure built	1959	1967