Castlio Elem.
St Charles, MO · Elementary School
Castlio Elem. is a elementary school in St Charles, MO with 818 students enrolled and a 68% proficiency rate. Part of Francis Howell R-III. NCES data from the U.S. Department of Education.
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About This School
Castlio Elem. is a elementary school located in St Charles, Missouri. The school serves 818 students. The student-to-teacher ratio is 13.2:1.
According to EDFacts assessment data, 68% of students meet grade-level proficiency standards in combined math and reading.
12% of students qualify for free or reduced-price lunch.
Castlio Elem. is part of the Francis Howell R-III in Missouri.
How This School Compares
Castlio Elem. has 818 students enrolled, making it larger than the average school in Francis Howell R-III (815 students). Its 68% proficiency rate is 2 percentage points above the district average of 66%. Compared to the Missouri state average of 49%, the school performs 19 points higher. With a 13.2:1 student-teacher ratio, it offers smaller class sizes than the national average.
Frequently Asked Questions
Castlio Elem. has 818 students enrolled. The student-to-teacher ratio is 13.2:1.
According to EDFacts data, 68% of students at Castlio Elem. meet grade-level proficiency standards in combined math and reading assessments.
Castlio Elem. is part of the Francis Howell R-III in St Charles, Missouri. You can view all schools in this district on the district page.
All data on this page comes from the National Center for Education Statistics (NCES) Common Core of Data and EDFacts assessment results. These are official federal datasets published by the U.S. Department of Education.
School profiles are built from NCES directory data and EDFacts assessment results. Proficiency rates reflect combined math and reading performance. Graduation rates are reported for high schools with available data.
The this entity record above pulls directly from NCES Common Core of Data and EDFacts. What follows is the per-entity context — how this entity sits in the broader U.S. K-12 school outcomes and enrollment distribution and which underlying factors drive the headline numbers.
The methodology behind every numeric value on this page is publicly documented on the NCES Common Core of Data and EDFacts portal and described in detail on this site’s methodology page. Refresh cadence varies by underlying series; the page surfaces the as-of date for each number so readers can trace any figure back to the source release.
For readers using this page as a decision input, the related-entity pages elsewhere on the site provide the comparison set. The most useful comparison for this entity is typically a peer within U.S. public schools and districts with similar size, similar exposure, or similar geography — not the national-level summary alone.
Source: NCES Common Core of Data, 2026.