DescriptionAging has become a serious problem for nations around the world. Senior populations have increased rapidly in recent decades, and now we have a variety of ways to enjoy retired life. Especially for seniors in an urban area, aging in place can keep seniors from moving to an unfamiliar environment and stay with their families and friends. Healing garden design principles can help to improve seniors' living environments by creating benefits in terms of physical activity, mental restoration, mental stimulation, and connection with community. This paper explores how research into the theories of healing gardens may help design to increase benefits to senior parks and gardens. This thesis project aims to apply senior-friendly design intervention to an urban outdoor space currently well-used by seniors. Columbus Park, in New York City, was selected after an analysis of demographics, senior facilities, and their proximity to existing open space. Two case studies analyze how the application of these design principles can influence seniors' experience of urban outdoor spaces. Conversation with existing park users and analysis of existing activities in Columbus Park contributed to the final design proposal.