Assets for a Healthy Adolescence - Experiential Outdoor Service Learning (AHA-EOSL) Program, provided by Rocky Mountain Youth Corps-CO (RMYC), engaged 165 youth during summer 2021 in Youth Crews (ages 14-18) who worked together in 8-10 member crews for two or five weeks and performed meaningful conservation and service projects. RMYC focused on enhancing eight protective factors 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. A quasi-experimental crossover design revealed that all eight factors showed effect size differences of 0.25 or greater, which indicated strong program outcomes. Additionally, while upon entrance more than 80% 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.]