Background: Built environments are associated with physical activity (PA), but most studies to date have employed acontextual PA outcome measures. The purposes of this study were to examine the proportion of PA that occurred within participants’ neighborhoods and associations between neighborhood walkability attributes and different intensities and purposes of PA episodes occurring specifically within neighborhoods. Methods: 384 community residents completed 7 subscales of the Neighborhood Environment Walkability Scale (NEWS) and a detailed 7-day PA log-booklet that included the duration, intensity, and purpose of all episodes. Results: Only one-third of reported PA episodes occurred in participants’ neighborhoods. Higher ratings for 5 of the 7 walkability variables were associated with an increased likelihood of engaging in at least some moderate-intensity neighborhood PA (versus none), but were not significantly associated with engaging in greater levels of neighborhood PA (150+ versus 1–149 minutes). Land use mix access, street connectivity, and aesthetics were significant predictors of transportation-related neighborhood PA, but only aesthetics was significantly associated with neighborhood recreational PA. Conclusions: Improving neighborhood walkability may be a stimulus for increased neighborhood PA, especially among largely sedentary individuals, but different attributes are associated with transportation-related and recreational activity.