Haddam-Killingworth High School
Higganum, CT · High School · Grades 9-12
Haddam-Killingworth High School is a high school in Higganum, CT with 546 students enrolled and a 73% proficiency rate. Part of Regional School District 17. NCES data from the U.S. Department of Education.
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About This School
Haddam-Killingworth High School is a high school located in Higganum, Connecticut. The school serves 546 students in grades 9-12. The student-to-teacher ratio is 10.7:1.
According to EDFacts assessment data, 73% of students meet grade-level proficiency standards in combined math and reading. The school reports a 89% graduation rate.
12% of students qualify for free or reduced-price lunch.
Haddam-Killingworth High School is part of the Regional School District 17 in Connecticut.
How This School Compares
Haddam-Killingworth High School has 546 students enrolled, making it larger than the average school in Regional School District 17 (360 students). Its 73% proficiency rate is 7 percentage points above the district average of 66%. Compared to the Connecticut state average of 53%, the school performs 20 points higher. With a 10.7:1 student-teacher ratio, it offers smaller class sizes than the national average.
Frequently Asked Questions
Haddam-Killingworth High School has 546 students enrolled in grades 9-12. The student-to-teacher ratio is 10.7:1.
According to EDFacts data, 73% of students at Haddam-Killingworth High School meet grade-level proficiency standards in combined math and reading assessments.
Haddam-Killingworth High School has a 89% graduation rate, measuring the percentage of students who graduate within four years.
Haddam-Killingworth High School is part of the Regional School District 17 in Higganum, Connecticut. 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.
For this entity, the underlying data on this page comes from NCES Common Core of Data and EDFacts. The breakdown above is the federal record; the paragraphs below add the per-entity context that makes the headline numbers usable for a real decision rather than just a data lookup.
Every number on this page links back to NCES Common Core of Data and EDFacts; the methodology page describes the inputs, refresh cadence, and known limitations of the underlying data product.
Practical use of this page is in combination with the comparison and ranking pages elsewhere on the site, which surface the same data for this entity’s peers within U.S. public schools and districts. A single-entity reading without peer context can be misleading when an entity is an outlier on one axis but typical on another.
Source: NCES Common Core of Data, 2026.