| Index | Plymouth | Illinois | National |
| Average Test Scores | n/a | 33% | 48% |
| Student/Teacher ratio | n/a | 18:1 | 16:1 |
| Total public schools | n/a | 3,938 | 79,221 |
| Total private schools | n/a | 1,438 | 24,874 |
| Total post-secondary schools | n/a | 306 | 7,963 |

| Index | Plymouth | Illinois | National |
| Completed 8th grade | 76.0% | 86.2% | 84.3% |
| Completed high school | 74.4% | 84.7% | 83.0% |
| Completed some college | 31.9% | 61.8% | 59.4% |
| Completed associate degree | 14.1% | 40.7% | 38.5% |
| Completed bachelors | 7.0% | 32.9% | 30.3% |
| Completed masters | 1.3% | 12.7% | 11.5% |
| Completed professional degree | 0.0% | 3.4% | 3.3% |
| Completed doctorate | 0.0% | 1.2% | 1.3% |
There are a total of n/a public schools, n/a private schools and n/a post-secondary schools in Plymouth. Using the proficiency score averages, the average test scores for Plymouth, IL schools is n/a. The average student to teacher ratio is n/a. In Plymouth, IL, an average of 76.0% of students have completed 8th grade and an average of 74.4% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Bowen, IL | 599 | 40% | 17.7% |
| Carthage, IL | 2,563 | 39% | 19.4% |
| Macomb, IL | 18,071 | 30% | 37.0% |
| Augusta, IL | 628 | 30% | 38.5% |
| Colchester, IL | 1,383 | 26% | 46.4% |
| Plymouth, IL | 451 | n/a |
| City | Population | Avg. Test Scores | National Avg. |
| Ropesville, TX | 451 | 49% | 2.1% |
| Lake City, CO | 451 | 40% | 16.7% |
| Hanover, MI | 452 | 53% | 9.4% |
| Foyil, OK | 450 | 21% | 56.9% |
| Claflin, KS | 452 | 30% | 37.5% |
| Plymouth, IL | 451 | n/a |