Summary:
ZIP code 91762 has two public high schools serving grades 9–12: Chaffey High and Ontario High. In 2025–26 all-grades results, both schools were above the state in English language arts (ELA), but below it in math and science. The clearest shared academic concern is math: proficiency was 22% at Chaffey and 29% at Ontario, compared with 38% statewide.
Neither school leads across every subject. Ontario High had the stronger ELA and math results: 54% versus 53% in ELA, and 29% versus 22% in math—a 7-point lead in math. Chaffey High led in science, with 32% proficiency compared with Ontario’s 29%. Both schools’ ELA results were above the state’s 49%, while both remained below the state in science. Ontario also had the higher graduation rate, 96% versus 91%, and the lower dropout rate, 5% versus 9%. However, chronic absenteeism was higher than the state’s 18% at both schools: 24% at Ontario and 27% at Chaffey.
Recent changes show a mixed picture: science improved at both schools, while ELA declined. From 2024–25 to 2025–26, science proficiency rose 10 percentage points at Chaffey and 9 at Ontario; ELA fell 6 points and 8 points, respectively, while the state’s ELA result rose by about half a point. SchoolDigger’s statewide rankings were relatively steady for Chaffey, which moved from the 58th to the 57th percentile, but Ontario fell from the 66th to the 58th percentile from 2024–25 to 2025–26. In 2024–25, Ontario’s student-teacher ratio was 21.8, compared with 23.3 at Chaffey; its free/reduced lunch eligible share was 87%, versus 82% at Chaffey. These context measures are comparisons, not explanations of school results. The data cover only these two schools.
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