Charter Schools Directory

This directory lists the 100 largest US charter schools by total enrollment from the NCES Common Core of Data. A school appears here only if its federal CCD record carries the charter-status flag — we do not infer charter status from school name patterns or local press coverage. Where the school\'s authorizing district has reported math and reading assessment results to EDFacts, we display the district-level proficiency rate alongside enrollment. The same fields are queryable programmatically through the Urban Institute Education Data API.

At 20,355 students, Commonwealth Charter Academy CS (Harrisburg, PA) is one of the largest schools of any kind in the country — a campus closer in scale to a small college than a typical neighborhood school. It heads a list where the second-place charter, Epic Charter School Elementary, enrolls 15,223 students.

This page lists charter schools as flagged in the NCES Common Core of Data. The status flag is set by the school's authorizer record, not by performance criteria. Sorting is by total enrollment.

Charter schools in NCES data are publicly funded, tuition-free, and operate under an authorizer-issued charter that grants more flexibility on staffing and curriculum than a traditional district school. Performance varies enormously across the sector — research from CREDO at Stanford and the National Bureau of Economic Research has consistently found wide dispersion: some networks meaningfully outperform district averages, others underperform, and most are roughly comparable.

By level, the list breaks down to roughly 0 elementary, 3 middle, and 97 high charter schools, with 0 configured as Other (typically K-12 or grade-band-spanning campuses common in the charter sector). Among the schools with a published EDFacts proficiency rate, a district-level rate close to the national middle, where roughly half of tested students reach grade-level standards on EDFacts assessments.

A large charter often signals an established, multi-campus network — KIPP, IDEA, Uncommon, Mater Academy, BASIS — that has scaled by replication and lottery-based expansion. Big enrollment is not a quality signal in either direction; it does, however, indicate sustained parent demand and authorizer renewal across multiple charter cycles. Smaller charters can be just as effective and are often more mission-specific (single-sex, language immersion, classical curriculum, special-needs focused).

Charter performance research is contested. CREDO\'s national charter studies have found average gains in urban charter networks but flat or negative effects in some non-urban settings. Read aggregate stats with care; individual school outcomes vary enormously and depend heavily on authorizer rigor, principal tenure, and teacher staffing.

A few honest caveats: EDFacts proficiency and graduation rates are reported at the district level, not the individual school. We apply the district number to every school in that district so that the comparison is at least consistent — but a strong school inside a struggling district will look worse than it is, and vice versa. NCES publishes the most recent year of CCD data with about a one-year lag. Privacy suppression hides results for very small subgroups, which appears as missing data rather than zero.

We filter NCES CCD to schools where the charter status flag is set, sort by total enrollment, and keep the top 100. We do not adjust the federal numbers or substitute network-published data. EDFacts proficiency rates are joined at the district level. For the full data lineage, see the methodology page.