Studies have found that urban sprawl explains many regional differences in BMI and walking behavior. Yet, African Americans, who often live in dense, urban neighborhoods with exemplar street connectivity, suffer disproportionately from obesity. This study analyzed walking and BMI among 1124 Whites and 691 Blacks in Los Angeles County and southern Louisiana in relation to neighborhood safety, street connectivity, and walking destinations. While the built environment partly explains regional differences in walking and BMI among Whites, the magnitude of effect was modest. There were no regional differences in outcomes for African Americans; individual rather than neighborhood characteristics served as the best predictors.