The present dissertation focused on influences of the built and natural environment on mental and physical health. Three studies examined environmental attributes associated with mental and physical health within children's most proximate settings: homes, neighborhoods, and schools: Chapter 2: Research about how residential design attributes may moderate effects of crowding on children's psychological health is sparse. This two-part, cross-sectional study first examined the relation between residential interior density and self-reported crowding among children. Second, analysis investigated the potential role of residential design attributes - floor plan arrangement, child's bedroom ceiling height, volume, and window area - to buffer adverse effects of crowding on children's psychological health and physiological stress. Results suggested that bedroom ceiling height may moderate negative effects of home and bedroom crowding on children's psychological health and physiological stress. Chapter 3: The amount of nature needed for humans to achieve the welldocumented benefits of nature exposure is unknown, partially because no common nature measure exists. This study developed and tested a nature estimation method, using freely available Google Earth satellite images, to address estimation limitations of 2006 National Land Cover Database and automated Geographic Information Systems procedures. Amounts of nature (vegetation, trees, water) surrounding a sample of New York residences were estimated and compared using both methods. The Google Earth method better estimated nearby nature in dense, highly developed urban areas, while either estimation method was appropriate for less densely populated areas. Chapter 4: Based on environmental psychology and behavioral economics strategies associated with healthy eating, the Cafeteria Assessment for Elementary Schools (CAFES) offers an objective, reliable, and valid instrument that quantifies physical cafeteria attributes linked to selection and consumption of fruits and vegetables (FV) at the scale of room, table, plate, and food. Observations, interviews, and FV serving and consumption data obtained from lunch tray photography were used to develop and validate CAFES. Total CAFES and four scale scores were associated with FV consumption outcomes. Researchers and practitioners can use CAFES to identify critical areas for intervention; suggest low- and nocost intervention strategies; and contribute to design guidelines aimed at promoting healthy eating among elementary school students.