Best Public Schools in Port Byron, IL

Port Byron, Illinois, has three schools in Riverdale CUSD 100, serving students from prekindergarten through grade 12 and enrolling 1,095 students altogether. The elementary and middle schools’ 2025–2026 all-grades IAR results are well above state figures: their school-level averages are 76% in ELA versus 56% statewide, and 56% in math versus 40% statewide. The clearest takeaway is that elementary and middle students perform strongly overall compared with state results, though middle-school math is a relative weak spot.

Riverdale Elementary School stands out in math, with 60% proficient compared with 52% at Riverdale Middle School—an 8-point difference. Both exceed the state in math, but the advantage is larger for elementary: 21 points versus 13. ELA results are close: 76% at elementary and 75% at middle, each about 19–20 points above state. The high school’s results vary by grade: 11th-grade ACT proficiency was above state in ELA and math by 12 and 11 points, while 10th-grade PreACT Secure ELA was 9 points below state. SchoolDigger ranks elementary at the 82nd percentile with 4 stars, middle at the 74th percentile with 4 stars, and Riverdale Senior High School at the 70th percentile with 3 stars.

Elementary and middle ELA results improved from 2024–2025, while their average math advantage over the state was nearly unchanged. The high school’s 11th-grade ACT scores remained above state, but its leads narrowed; its 10th-grade ELA result also shifted from above state to below. SchoolDigger percentile rankings declined since 2023–2024: 2 points at elementary, 4 at middle, and 10 at the high school. In 2024–2025, student-teacher ratios were 12.9 at elementary, 14.1 at middle, and 11.8 at the high school; each school reported a free/reduced lunch eligible share of about 16% for that school year. The high school’s 2025–2026 graduation rate was 96%, compared with 90% statewide, while chronic absenteeism was 20%, higher than the district’s 13%. Grade-level results and assessments are not directly interchangeable, so comparisons across schools should be read with that in mind.