This study looked at whether access to Board Certified Behavior Analysts for children with autism spectrum disorder is different between U.S. counties. The study included all U.S. counties and county equivalents in 48 states and D.C. ( = 3108). Between March and May 2019, we combined data from the U.S. Department of Education’s Civil Rights Data Collection, Behavior Analyst Certification Board’s certificant registry, and U.S. Census. We assigned Board Certified Behavior Analysts to counties based on their address, matched children in school districts to counties, and determined how many children with autism spectrum disorder there were in a county compared with how many Board Certified Behavior Analysts there were in a county. The results show uneven numbers of Board Certified Behavior Analysts between U.S. counties. More than half of all counties had no Board Certified Behavior Analysts. National maps illustrate clusters of high and low accessibility to Board Certified Behavior Analysts. To improve access to Board Certified Behavior Analysts in underserved areas, we must identify what contributes to the differences in access.