Assets for a Healthy Adolescence - Experiential Prevention (AHA-EOSL) Program, provided by Rocky Mountain Youth Corps-CO (RMYC), engaged 165 youth during summer 2021 in Community Youth Crews (ages 14-15) or Regional Youth Crews (ages 16-18). Participants in both programs lived, camped (24/7), and worked together in 8-10 member crews for two or five weeks and performed meaningful conservation and service projects for public benefit six to eight hours per day. Evenings and weekends were spent doing daily living chores, AHA-EOSL Education Curriculum, outdoor recreation, and life skills development. All members were paid, and those 17 or older may have received AmeriCorps education awards. The program's purpose was to provide deep, immersive, and experiential absorption of life skills to ensure a healthy transition into adulthood. RMYC program developers focused on eight factors they believed would be positively enhanced by program participation, along with reductions in alcohol and marijuana use: 1. Planning and Decision Making, 2. Interpersonal Skills, 3. Peer/Social Support, 4. Resiliency, 5. Enhanced Self-Efficacy, 6. Leadership, 7. Civic Engagement, and 8. Alcohol and Drug Expectations. Evaluation data were collected online using Entrance and Exit Surveys. With the exception of Alcohol and Drug Expectations, all seven other prevention factors showed effect size differences pre/post of 0.25 or greater, which indicates strong program outcomes. Additionally, while upon entrance more than 85% of the participants reported no use of either alcohol or marijuana in the past 30 days, at exit, among those who did report use greater than 70% reported reduced use. [This report was commissioned by Rocky Mountain Youth Corps-CO.]