| Index | Custer | South Dakota | National |
| Average Test Scores | 50% | 48% | 48% |
| Student/Teacher ratio | 12:1 | 14:1 | 16:1 |
| Total public schools | 6 | 340 | 79,221 |
| Total private schools | n/a | 76 | 24,874 |
| Total post-secondary schools | n/a | 25 | 7,963 |
| Index | Custer | South Dakota | National |
| Completed 8th grade | 89.6% | 89.1% | 84.3% |
| Completed high school | 86.1% | 86.8% | 83.0% |
| Completed some college | 59.5% | 60.4% | 59.4% |
| Completed associate degree | 33.6% | 38.5% | 38.5% |
| Completed bachelors | 22.9% | 27.5% | 30.3% |
| Completed masters | 4.2% | 8.1% | 11.5% |
| Completed professional degree | 0.9% | 2.5% | 3.3% |
| Completed doctorate | 0.8% | 1.2% | 1.3% |
There are a total of 6 public schools, n/a private schools and n/a post-secondary schools in Custer. Using the proficiency score averages, the average test scores for Custer, SD schools is 50%. The average student to teacher ratio is 12:1. In Custer, SD, an average of 89.6% of students have completed 8th grade and an average of 86.1% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Hill City, SD | 587 | 62% | 29.5% |
| Custer, SD | 2,314 | 50% | 3.1% |
| City | Population | Avg. Test Scores | National Avg. |
| Petersburg, IN | 2,315 | 38% | 20.1% |
| Brownsville, PA | 2,313 | 34% | 29.5% |
| Zwolle, LA | 2,312 | 68% | 40.6% |
| Chiefland, FL | 2,312 | 51% | 5.7% |
| Collinsville, AL | 2,312 | 25% | 49.0% |
| Custer, SD | 2,314 | 50% | 3.1% |
Here are the best places to live in South Dakota
These are the 10 cheapest cities in South Dakota
See the best places to live in Custer
Check out the 10 most dangerous cities in South Dakota