| Index | Letcher | South Dakota | National |
| Average Test Scores | n/a | 48% | 48% |
| Student/Teacher ratio | n/a | 14:1 | 16:1 |
| Total public schools | n/a | 340 | 79,221 |
| Total private schools | n/a | 76 | 24,874 |
| Total post-secondary schools | n/a | 25 | 7,963 |
| Index | Letcher | South Dakota | National |
| Completed 8th grade | 90.7% | 89.1% | 84.3% |
| Completed high school | 89.8% | 86.8% | 83.0% |
| Completed some college | 57.6% | 60.4% | 59.4% |
| Completed associate degree | 24.6% | 38.5% | 38.5% |
| Completed bachelors | 10.2% | 27.5% | 30.3% |
| Completed masters | 5.1% | 8.1% | 11.5% |
| Completed professional degree | 1.7% | 2.5% | 3.3% |
| Completed doctorate | 1.7% | 1.2% | 1.3% |
There are a total of n/a public schools, n/a private schools and n/a post-secondary schools in Letcher. Using the proficiency score averages, the average test scores for Letcher, SD schools is n/a. The average student to teacher ratio is n/a. In Letcher, SD, an average of 90.7% of students have completed 8th grade and an average of 89.8% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Forestburg, SD | 78 | 57% | 18.1% |
| Woonsocket, SD | 748 | 52% | 8.9% |
| Mitchell, SD | 15,599 | 52% | 8.7% |
| Artesian, SD | 181 | 50% | 4.2% |
| Mount Vernon, SD | 500 | 48% | 0.7% |
| Letcher, SD | 191 | n/a |
| City | Population | Avg. Test Scores | National Avg. |
| Chugwater, WY | 191 | 50% | 4.2% |
| Mellette, SD | 191 | 50% | 4.2% |
| Ruby, AK | 190 | 25% | 47.9% |
| Caledonia, MO | 190 | 40% | 17.7% |
| Plaucheville, LA | 190 | 63% | 31.3% |
| Letcher, SD | 191 | n/a |
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