Abstract: A population health perspective in mental health shifts attention from interventions delivered at the individual level to broad determinants, such as neighborhood characteristics, that impact the mental health of communities. The walkability of an environment has emerged as a potentially important determinant of mental health, but little research has explored relationships between walkable environments and depression. Additionally, though PTSD symptoms could interfere with the potential benefits of walkable environments on depression, such an effect has not yet been tested. Using binomial logistic regression, we examined relationships between objective walkability and four perceived environmental features in one's home neighborhood (infrastructure for walking/cycling, aesthetics, traffic safety, and safety from crime) with current depression (≥10 on PHQ-8) in a sample of treatment-seeking veterans also assessed for PTSD symptoms. Lower perceived safety from crime, but not objective walkability, was associated with depression. Higher perceived neighborhood aesthetics was associated with lower depression but not after accounting for physical activity. Perceived safety from crime was not significantly associated with depression in a subsample screening positive for PTSD, suggesting that this indicator of perceived neighborhood characteristics is less impactful among those with greater comorbidity risk. Higher physical activity was associated with less likelihood of depression but not in the subsample screening positive for PTSD. Implementing measures to improve impressions of neighborhood safety and aesthetics may be promising paths to enhancing physical and mental health in the veteran population.