The purpose of this study was to quantify the agreement between perceived and objective measures of the natural environment and to assess their associations with physical activity. Perception of the natural environment was obtained through survey data. Objective measures of weather and hills were created using Geographic Information Systems (GIS). When objective measures were compared to respondent's perceptions little agreement was found. Objective measures were not associated with any physical activity outcomes; however, several associations were seen between perceived measures and physical activity. These results indicate that researchers should consider perceptions of the natural environment when developing physical activity interventions.