| Index | Onarga | Illinois | National |
| Average Test Scores | 33% | 33% | 48% |
| Student/Teacher ratio | 10:1 | 18:1 | 16:1 |
| Total public schools | 2 | 3,938 | 79,221 |
| Total private schools | n/a | 1,438 | 24,874 |
| Total post-secondary schools | n/a | 306 | 7,963 |
| Index | Onarga | Illinois | National |
| Completed 8th grade | 65.0% | 86.2% | 84.3% |
| Completed high school | 62.5% | 84.7% | 83.0% |
| Completed some college | 36.4% | 61.8% | 59.4% |
| Completed associate degree | 15.3% | 40.7% | 38.5% |
| Completed bachelors | 7.8% | 32.9% | 30.3% |
| Completed masters | 1.6% | 12.7% | 11.5% |
| Completed professional degree | 0.4% | 3.4% | 3.3% |
| Completed doctorate | 0.0% | 1.2% | 1.3% |
There are a total of 2 public schools, n/a private schools and n/a post-secondary schools in Onarga. Using the proficiency score averages, the average test scores for Onarga, IL schools is 33%. The average student to teacher ratio is 10:1. In Onarga, IL, an average of 65.0% of students have completed 8th grade and an average of 62.5% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Crescent City, IL | 485 | 45% | 6.3% |
| Cissna Park, IL | 847 | 43% | 10.4% |
| Piper City, IL | 855 | 42% | 12.5% |
| Gilman, IL | 1,734 | 41% | 15.1% |
| Thawville, IL | 225 | 37% | 22.9% |
| Onarga, IL | 1,134 | 33% | 32.3% |
| City | Population | Avg. Test Scores | National Avg. |
| Allison, IA | 1,134 | 75% | 55.2% |
| Wickes, AR | 1,133 | 57% | 18.8% |
| Cottonwood, AL | 1,133 | 46% | 4.2% |
| Puxico, MO | 1,133 | 31% | 35.4% |
| Sterling City, TX | 1,135 | 47% | 2.1% |
| Onarga, IL | 1,134 | 33% | 32.3% |
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