Summary:
ZIP code 06870 is served by a single, exceptionally high-performing public elementary school — Old Greenwich School — which enrolls 385 students in grades PK through 5 and is part of the highly regarded Greenwich School District, ranked 14th out of 153 districts in Connecticut with a 5-star rating. Because there are no middle or high schools within this ZIP code, families in 06870 continue into other schools within the district for secondary education.
Old Greenwich School is a standout by any measure, earning a 5-star rating and ranking in the top 4% of Connecticut elementary schools for three consecutive years: 12th in the state in 2025–2026, 4th in 2024–2025, and 20th in 2023–2024. The school’s academic performance is far above state averages across every subject and grade level. For example, 3rd-grade math proficiency reached 92.5% in 2025–2026 versus 52.2% statewide, and 4th-grade ELA hit 86.4% compared with 50.9% statewide. The school also benefits from an extremely low free/reduced-price lunch eligibility rate of 2.34%, a low student–teacher ratio of 10.5, and very high per-pupil spending of $33,050, all contributing to a well-resourced learning environment. Chronic absenteeism stands at 9.6%, lower than the state average of 16.4% but slightly above the district’s 8.5%.
One notable trend is a 5th-grade dip in the most recent year: ELA proficiency fell from 93.7% to 79.3%, and math from 85.7% to 74.1%, causing 5th-grade scores to fall below the district average for the first time. Even so, those results remain well above state levels, and math in the early grades remains a clear strength, with 3rd and 4th grade both above 90% proficient in 2025–2026. Overall, Old Greenwich School is an elite, richly funded elementary school with a track record of outstanding outcomes, though families should monitor the developing 5th-grade trend as students transition to the middle grades.
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