| Index | Custer | Montana | National |
| Average Test Scores | 30% | 45% | 48% |
| Student/Teacher ratio | n/a | 14:1 | 16:1 |
| Total public schools | n/a | 408 | 79,221 |
| Total private schools | n/a | 77 | 24,874 |
| Total post-secondary schools | n/a | 32 | 7,963 |
| Index | Custer | Montana | National |
| Completed 8th grade | 85.1% | 89.4% | 84.3% |
| Completed high school | 83.3% | 88.2% | 83.0% |
| Completed some college | 49.1% | 63.1% | 59.4% |
| Completed associate degree | 22.8% | 38.6% | 38.5% |
| Completed bachelors | 19.3% | 29.9% | 30.3% |
| Completed masters | 7.9% | 9.8% | 11.5% |
| Completed professional degree | 0.0% | 3.0% | 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 Custer. Using the proficiency score averages, the average test scores for Custer, MT schools is 30%. The average student to teacher ratio is n/a. In Custer, MT, an average of 85.1% of students have completed 8th grade and an average of 83.3% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Custer, MT | 151 | 30% | 37.5% |
| City | Population | Avg. Test Scores | National Avg. |
| Kobuk, AK | 151 | 20% | 58.3% |
| Palmetto, LA | 151 | 92% | 91.7% |
| Winterhaven, CA | 151 | 23% | 52.3% |
| Brookeville, MD | 151 | 66% | 37.5% |
| Edgar Springs, MO | 151 | 62% | 29.2% |
| Custer, MT | 151 | 30% | 37.5% |
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