This study evaluated the extent to which two systematic observation protocols which were modified for underserved communities (low income, minorities) could be utilized to reliably assess (a) use of walking trails and (b) physical environmental features of these trails. This study was a supplement to the Positive Action for Today’s Health (PATH) walking trial. The modified tools were shown to be reliable methods for (a) measuring trail use and (b) assessing physical features of the trail in underserved environments. Reliability data for measuring trail use were found to be high (ICC=.98, p<.01). Reliabilities for measuring features of the trail ranged from fair to highly reliable (κ=.77−1.00; ICC=.34–1.00). The observation tools that were customized for this study were shown to be reliable instruments for measuring trail use and assessing physical features of walking trails in underserved communities.