National city placement
One campus shapes the city average
According to NCES CCD 2024-25, Millbrae has more public-school enrollment than 28% of the 4,487 US cities in this directory. Mills High enrolls 37.9% of Millbrae's public-school students. That is enough concentration for one institution to pull the citywide enrollment, staffing, and Resource Index averages toward its own profile. The smaller campuses below should therefore be compared directly rather than inferred from the headline mean; their grade configurations and program footprints can be materially different even inside the same district.
The school portfolio is elementary-weighted
3 of Millbrae's 5 listed schools are elementary campuses. That composition means citywide enrollment and staffing averages are influenced more by early-grade operating patterns than by the city's 1 middle and 1 high-school records. Families comparing later grades should rely on those individual rows rather than the all-school mean.
Campus spread matters more than the city mean
The 15-point gap between Mills High and Green Hills Elementary shows the range hidden by Millbrae's average Resource Investment Index. The city figure is useful for national placement, but families ultimately choose among campuses with different grade spans, enrollment, district affiliations, and reported support fields. Start with schools serving the relevant grade level, then compare the index components rather than assuming the city average describes any one classroom.
