The distribution of natural spaces within cities creates profound ripple effects on mental and physical health outcomes that extend far beyond simple proximity measurements. Understanding these patterns becomes crucial as urban populations swell and environmental stressors intensify across metropolitan areas worldwide. This comprehensive analysis reveals how accessibility to parks, waterways, and green corridors operates as a fundamental determinant of population wellbeing, with measurable impacts on stress reduction, cognitive function, and community resilience. The research demonstrates that blue spaces like rivers and lakes provide distinct psychological benefits compared to traditional green spaces, particularly for stress recovery and attention restoration. Geographic accessibility patterns show systematic disparities, with lower-income neighborhoods experiencing reduced access to high-quality natural environments by margins of 40-60% compared to affluent areas. These gaps translate into quantifiable health differences, including elevated cortisol levels, reduced sleep quality, and higher rates of anxiety-related disorders among populations with limited nature access. The findings challenge conventional urban planning approaches that treat green infrastructure as amenities rather than essential health infrastructure. Current evidence suggests that equitable distribution of natural spaces could serve as a scalable intervention for addressing urban mental health disparities. However, the research highlights critical limitations around causality - while associations between nature access and wellbeing are robust, determining whether improved access directly causes better health outcomes requires longer-term longitudinal tracking. This work represents an important step toward evidence-based urban design that prioritizes psychological wellbeing alongside traditional infrastructure needs, though implementation will require coordinated policy changes across multiple municipal domains.