OBJECTIVE : Road intersection density is an important indicator of walkability. The objectives of this study were to examine the trends in intersection density in the US from 2007 to 2011 and assess the associations between intersection density and childhood obesity risk at the state level. METHODS : Longitudinal analyses were conducted to assess the spatial-temporal changes of population-weighted intersection density in relation to the risk of childhood obesity in the US. METHODS : Road network data from the Topologically Integrated Geographic Encoding and Referencing (TIGER) (2007-2011), the prevalence of overweight and obesity data from the National Survey of Children's Health (NSCH) (2007-2011), and the American Community Survey (ACS) (2011) were used. Geographic information system (GIS) visualization and spatial and regression analyses were conducted. Mixed-effect models were fit to assess the longitudinal relationship between intersection density and childhood obesity. RESULTS : Between 2007 and 2011, population-weighted intersection density remained relatively stable in most states. Low-intersection-density states were clustered in the Southeastern region in both 2007 and 2011. The high-intersection-density states were clustered in the Middle Atlantic Division. California and Nevada also were identified as high-intersection-density clusters in 2011. States with lower road intersection density corresponded with states with higher childhood obesity prevalence. Our mixed-effect model estimates suggested that increased intersection density was associated with decreased obesity prevalence. CONCLUSIONS : This study provided empirical evidence for longitudinal associations between neighborhood intersection density and childhood obesity prevalence based on national data and offered a new perspective of the role that road network plays in childhood obesity prevention.