Best High Schools in Zip Code 83604

Zip code 83604 is home to just one high school, Rimrock Junior/Senior High School, a small rural school in Bruneau, Idaho, serving grades 6 through 12 with only 136 students. The school belongs to the Bruneau-Grand View Joint School District and currently holds a 4-star rating, ranking #34 out of 122 Idaho high schools (72nd percentile) for 2025–2026 — a dramatic jump from its 1-star ranking and 27th percentile the previous year. This strong current-year performance is driven by notable strengths in English Language Arts and End-of-Course Science, where the school beats both district and state averages, while its small student body means individual student results can have an outsized impact on school-wide metrics.

Academically, Rimrock’s most impressive results are in ELA and science: the all-grades ELA proficiency rate is 56.9%, above the state’s 54.0%, and End-of-Course Science proficiency is 57.1%, far exceeding Idaho’s 41.2% average. The school also outperforms the state in End-of-Course Math (38.1% vs. 33.1%) and End-of-Course ELA (66.7% vs. 61.3%). However, middle school math remains a clear weak spot, with 7th grade math proficiency at just 28.6% compared to the state’s 43.6%, and all middle school grades lag behind their state peers in math. Chronic absenteeism is another concern, sitting at 23.1% — nearly double the state rate of 13.8% — which can hurt academic consistency, especially in such a small school.

Families should also note that more than half of Rimrock’s students (51.47%) qualify for free or reduced-price lunch, indicating a majority low-income student body, yet the school still manages to compete with or exceed state averages in ELA and science. That said, some data should be viewed cautiously: the reported graduation rate of 82.5% appears identical for the school, district, and state, suggesting a possible reporting artifact, and the per-student spending figure of $11,846 dates back to 2018–2019. Overall, Rimrock Junior/Senior High School offers strong ELA and science outcomes and an encouraging recent ranking boost, but its middle school math gaps and chronic absenteeism are important areas to watch, especially given how much a few students can change results from year to year.