Purpose-To validate a commercial database of community-level physical activity facilities that can be used in future research examining associations between access to physical activity facilities and individual-level physical activity and obesity.Methods-Physical activity facility characteristics and locations obtained from a commercial database were compared to a field census conducted in 80 Census block groups within two U.S. communities. Agreement statistics, agreement of administratively-defined neighborhoods, and distance between locations were used to quantify count, attribute, and positional error.Results-There was moderate agreement (concordance: non-urban: 0.39; urban: 0.46) of presence of any physical activity facility and poor to moderate agreement (kappa range: 0.14 to 0.76) of physical activity facility type. The mean Euclidean distance between commercial database versus field census locations was 757 and 35 meters in the non-urban and urban communities, respectively. However, 94 and 100% of non-urban and urban physical activity facilities, respectively, fell into the same 5-digit ZIP code, dropping to 92 and 98% in the same block group and 71% along the same street.Conclusions-Our findings suggest that the commercial database of physical activity facilities may contain appreciable error, but patterns of error suggest that built environment-health associations are likely biased downward.