Prior epidemiological studies investigating the association between delivery mode (i.e., vaginal birth and cesarean section [C‐section]) and autism spectrum disorder (ASD) and intellectual disability (ID) risk have reported mixed findings. This study examined ASD and ID risks associated with primary and repeat C‐section within diverse US regions. During even years 2000–2016, 8‐years‐olds were identified with ASD and/or ID and matched to birth records [ASD only (N = 8566, 83.6% male), ASD + ID (N = 3445, 79.5% male), ID only (N = 6158, 60.8% male)] using the Centers for Disease Control and Prevention's Autism and Developmental Disabilities Monitoring Network methodology. The comparison birth cohort (N = 1,456,914, 51.1% male) comprised all births recorded in the National Center for Health Statistics corresponding to birth years and counties in which surveillance occurred. C‐section rates in the birth cohort demonstrated significant regional variation with lowest rates in the West. Overall models demonstrate increased odds of disability associated with primary and repeat C‐section. Adjusted models, stratified by region, identified significant variability in disability likelihood associated with repeat C‐section: increased odds occurred for all case groups in the Southeast, for ASD only and ID only in the Mid‐Atlantic, and no case groups in the West. Regional variability in disability risk associated with repeat C‐section coincides with differences in birth cohorts' C‐section rates. This suggests increased likelihood of disability is not incurred by the procedure itself, but rather C‐section serves as a proxy for exposures with regional variability that influence fetal development and C‐section rates.