Autism Rates by State: Two Federal Counts, One Common Misreading

Autism rates by state are published against two federal collections that answer two different questions.

The CDC Autism and Developmental Disabilities Monitoring Network estimates clinical prevalence. Surveillance year 2022, published 2025, covering children aged 8 across 16 monitored communities, reports 32.2 per 1,000, or about 1 in 31.

The U.S. Department of Education IDEA Section 618 child count is an administrative census of children ages 5 to 21 served in public schools under the autism eligibility category. For school year 2023-24, that is about 1 in 72 nationally.

The two figures do not conflict. A child can hold a clinical diagnosis and still not appear in the IDEA autism count, because the school serves that child under a different eligibility category, under a 504 plan, or in general education.

Within the IDEA count, the state spread reaches roughly 3.7 to 1. Massachusetts identifies about 1 in 51. Montana identifies about 1 in 188. Autism does not vary fourfold across a state line. Evaluation capacity, referral practice, and eligibility interpretation do. Iowa and New Mexico report non-categorically and publish no autism-specific count, so neither state can be ranked on this measure.

The practical consequence: a low state identification rate is not a favorable result. It usually means fewer children in that state have been evaluated.

Special Needs Care Network operates a directory of special needs schools and therapy providers in the United States at specialneedsusa.com. The full 50 state table, with both figures side by side and a downloadable CSV, is published at https://specialneedsusa.com/data/autism-rates-by-state

Sources named on that report: CDC ADDM 2022, U.S. Department of Education IDEA Section 618 for 2023-24, U.S. Census Bureau population estimates for 2023. Figures verified August 2026.