This study explored factors associated with age of identification of autism spectrum disorder (ASD). Results of a one-way ANOVA indicated differences in age of diagnosis among the four regions in the United States, F(3, 650) = 7.618, p = .01. Tukey’s post hoc comparisons of the groups indicated that the mean age of diagnosis in the Midwest (M = 38.9 months or 3 years, 3 months) was significantly later than in the Northeast (M = 32.75 months or 2 years, 9 months, p = .000) and South (M = 33.26 months or 2 years, 9 months, p = .000). Results of a Pearson correlation indicated a significant negative correlation (r = –.409, n = 654, p = .000) between date of birth and age of diagnosis, with more recent birthdays associated with lower age of diagnosis. Regression results were statistically significant, F(25, 620) = 7.549, p < .001, R² = .233, with some factors predicting earlier age of diagnosis and some factors predicting later diagnosis.