Figure S1. Mother’s educational attainment at the time of birth n=11,034. Map reflects the optimal span size of the ASD analyses (span=0.95; global P<0.001); the optimal span size of the education analysis was 0.05 (global P<0.001). Larger prevalence ratios indicate a higher prevalence of mothers with college or more education at the child’s birth. Areas of significantly increased and decreased risk are indicated by black contour bands. Figure S2. Adjusted maps for (A) ASD prevalence (birth cohort n=11,034 and ASD n=532), (B) ASD-ID (birth cohort n=11,034 and ASD-ID n=318), and (C) ASD+ID (birth cohort n=11,034 and ASD+ID n=214). Maps are not significantly different than flat (global P=0.052, global P=0.294 and global P=0.196, respectively). Adjustment factors were year of birth; plurality; maternal age, race, and level of education; and report of tobacco use during pregnancy.