| Index | Harristown | Illinois | National |
| Average Test Scores | n/a | 33% | 48% |
| Student/Teacher ratio | 15:1 | 18:1 | 16:1 |
| Total public schools | 1 | 3,938 | 79,221 |
| Total private schools | n/a | 1,438 | 24,874 |
| Total post-secondary schools | n/a | 306 | 7,963 |

| Index | Harristown | Illinois | National |
| Completed 8th grade | 79.6% | 86.2% | 84.3% |
| Completed high school | 78.9% | 84.7% | 83.0% |
| Completed some college | 41.9% | 61.8% | 59.4% |
| Completed associate degree | 18.6% | 40.7% | 38.5% |
| Completed bachelors | 12.4% | 32.9% | 30.3% |
| Completed masters | 1.2% | 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 1 public schools, n/a private schools and n/a post-secondary schools in Harristown. Using the proficiency score averages, the average test scores for Harristown, IL schools is n/a. The average student to teacher ratio is 15:1. In Harristown, IL, an average of 79.6% of students have completed 8th grade and an average of 78.9% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Stonington, IL | 686 | 50% | 4.2% |
| Forsyth, IL | 3,591 | 48% | 1.0% |
| Mount Zion, IL | 5,927 | 44% | 8.9% |
| Oreana, IL | 986 | 41% | 14.6% |
| Maroa, IL | 2,025 | 40% | 17.2% |
| Harristown, IL | 1,343 | n/a |
| City | Population | Avg. Test Scores | National Avg. |
| Fulda, MN | 1,343 | 56% | 16.1% |
| Melcher-Dallas, IA | 1,343 | 53% | 10.8% |
| Sand Lake, MI | 1,343 | 35% | 28.1% |
| Winthrop, MN | 1,343 | 50% | 4.2% |
| Larimore, ND | 1,343 | 46% | 4.7% |
| Harristown, IL | 1,343 | n/a |