Abstract The current study investigated affective and cognitive outcomes at pre, post and follow-up of 79 male and female Project Hahn wilderness program participants referred to the program through various agencies involved with employment, education, justice and welfare. The recurrent institutional design and selection of measures were based on an earlier empirical study by Sveen and Denholm (1997). Major findings include significant long-term effects reflecting greater participant self-actualisation (ES of .49) and decreased hopelessness (ES of .55). There was a more transitory increase in existential wellbeing. Police recidivist data indicated that 42 of 56 youth who had prior convictions did not re-offend in the two years following the wilderness intervention. Of 23 youth without prior convictions, 8 received convictions in this period. Overall, the study supports the continuing value of wilderness programs for at-risk youth.