| Index | Shelter Island | New York | National |
| Average Test Scores | 55% | 48% | 49% |
| Student/Teacher ratio | n/a | n/a | 16:1 |
| Total public schools | 1 | 4,060 | 79,235 |
| Total private schools | n/a | 1,092 | 24,875 |
| Total post-secondary schools | n/a | 483 | 7,965 |
| Index | Shelter Island | New York | National |
| Completed 8th grade | 97.3% | 83.2% | 83.8% |
| Completed high school | 97.3% | 81.6% | 82.4% |
| Completed some college | 79.3% | 58.4% | 58.4% |
| Completed associate degree | 68.3% | 42.2% | 37.2% |
| Completed bachelors | 56.4% | 33.7% | 29.3% |
| Completed masters | 28.0% | 14.6% | 11.0% |
| Completed professional degree | 4.3% | 4.1% | 3.2% |
| Completed doctorate | 2.3% | 1.4% | 1.3% |
| City, State | Population | Avg. Test Scores | National Avg. |
| East Hampton North, NY | 4,201 | 95% | 93% |
| Greenport, NY | 2,369 | 71% | 45% |
| Mattituck, NY | 4,391 | 70% | 42% |
| Amagansett, NY | 1,355 | 60% | 21% |
| Southampton, NY | 3,154 | 58% | 18% |
| Shelter Island, NY | 1,270 | 55% | 11% |
| City, State | Population | Avg. Test Scores | National Avg. |
| Monticello, WI | 1,270 | 45% | 10% |
| Elizabeth, CO | 1,270 | 38% | 23% |
| Fruitport, MI | 1,270 | 41% | 17% |
| Stryker, OH | 1,271 | 78% | 59% |
| Bethany, IL | 1,269 | 19% | 62% |
| Shelter Island, NY | 1,270 | 55% | 11% |