A−
Cos Cob School
PublicElementaryGrades PK–5
300 East Putnam Ave., Cos Cob, CT 06807 · (203) 869-4670 · Part of Greenwich School District
Students
343
Students per teacher
10:1
Free or reduced lunch
16%
Setting
Suburb
Grades
PK–5
What stands out about Cos Cob School
- School Grade A−: near the top of Connecticut’s public schools
- Math proficiency 24 pts above the state
- Reading / language arts 16 pts above the state
- Small classes: 10:1 students per teacher
- Next stop for Byram kids: 3 middle schools
On the path
Where Byram kids come from and go next.
PK–5Cos Cob SchoolYou are here
6–83 middle schoolsDepends on your address
Test scores
EDFacts via Urban Institute Education Data Portal (SY2020-21) · 2020–21Math proficiency62%
State average 37.9%
Reading / language arts67%
State average 50.7%
Location
Directions ↗
300 East Putnam Ave., Cos Cob
Students
Enrollment by grade
Pre-K24
Kindergarten52
Grade 152
Grade 260
Grade 358
Grade 450
Grade 547
Enrollment over time
362’20
359’21
337’22
340’23
343’24
Down 5.2% since 2020.
Who goes here
White 67%Hispanic 20%Asian 5%Two or more races 5%Black 1%American Indian/Alaska Native <1%
As reported to NCES, share of students with a reported race or ethnicity.
What neighbors say
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Parents talk
Conversations in Town Square that mention Cos Cob School.
Other schools in Greenwich School District
School facts: U.S. Department of Education (NCES), 2024-2025 school year. Scores: EDFacts via Urban Institute Education Data Portal (SY2020-21). The School Grade is our own summary of state test results. Neighbor ratings are opinions, not an official measure of school quality.