Neighborhoods influence children's health, so it is important to have measures of children's neighborhood environments. Using the Child Opportunity Index 2.0, a composite metric of the neighborhood conditions that children experience today across the US, we present new evidence of vast geographic and racial/ethnic inequities in neighborhood conditions in the 100 largest metropolitan areas in the US. Child Opportunity Scores range from 20 in Fresno, California, to 83 in Madison, Wisconsin. However, more than 90 percent of the variation in neighborhood opportunity happens within metropolitan areas. In 35 percent of these areas the Child Opportunity Gap (the difference between Child Opportunity Scores in very low- and very high-opportunity neighborhoods) is higher than across the entire national neighborhood distribution. Nationally, the Child Opportunity Score for White children (73) is much higher than for Black (24) and Hispanic (33) children. To improve children's health and well-being, the health sector must move beyond a focus on treating disease or modifying individual behavior to a broader focus on neighborhood conditions. This will require the health sector to both implement place-based interventions and collaborate with other sectors such as housing to execute mobility-based interventions.