Mills High

Mills High operates as a moderately sized secondary school in Millbrae, California, operated by San Mateo Union High. Current enrollment sits at 1,115 students spanning grades 9 through 12. That puts it 33% larger than the typical public school in California, which averages around 838 students.

Across the 8 schools in San Mateo Union High (8,736 students total), Mills High accounts for its share of the district's footprint.

Looking at the student body, Mills High reports that Asian students make up the majority at 59%; the rest looks like 20% Hispanic, 11% White, 9% multiracial. That is visibly more Asian than the county at large, where the share is closer to 31%.

Looking at school resources, On paper, Mills High has 54 full-time-equivalent teachers, translating to a class-load average of around 20.5:1. Statewide, the average ratio sits near 18.2:1, putting Mills High higher than the state norm the norm. Roughly 20% of students at Mills High qualify for free or reduced-price lunch, often used as a Title I proxy. By comparison, San Mateo County runs at roughly 34%, so the school's eligibility rate is meaningfully below the surrounding baseline.

On a residual basis (actual vs predicted given the student mix), Mills High performs roughly as the BeatsExpectations model predicts for a school with this FRL share. The predicted value is around 67.4%, the actual is 65.9%, a residual of -1.5 points.

In the area at large, the surrounding county (San Mateo County) logs that median household income runs about $158,855, 54% of adults hold a bachelor's degree or higher, and census figures put the poverty rate at about 4%. Mills High is one of 176 public schools in San Mateo County (combined enrollment of about 82,403 students).

The closest other public school is Spring Valley Elementary, roughly 0.2 miles away. Counting just inside five miles, 8 other public schools cluster around Mills High. On composite proficiency, Mills High comes 7th of 8 in the immediate cluster, behind the nearby-schools average of 75.1%.

The school occupies a bedroom-community site.

Five-year trend. Looking back 7 years, enrollment at Mills High has edged down 9%, going from 1,220 students in 2018 to 1,115 in 2025.

On this page, members of the Mills High community share and discuss sports schedules, lunch menu changes, and school spirit week. Anyone with firsthand experience at this school can post or comment.