This research is an exploration of the local, place-based knowledge surrounding a degraded urban river, the Lower Neponset River and Estuary in southern Boston Harbor, Massachusetts, and its environmental restoration. Through a mixed-methods approach to sociological inquiry that included 18-months of ethnographic interviews and participant observations, Geographic Information System (GIS) mapping, archival document research, and critical environmental history, it explores the different ways local citizens interpret the river as a place of historical importance, personal nostalgia, social and family networks, neighborhood legacies, aesthetics, economic security, danger, psychological refuge, ecology, and political power. Using an interpretive analysis of the narrative, visual, and spatial data related to those meanings, it then explores how such different local, place-based interpretations can be used to inform the theory, practice and politics of urban river restoration. The research shows that recognition of the socio-cultural diversity in local citizen interpretations of the Lower Neponset River's restoration is important for environmental managers, planners, and local decision-makers to recognize alongside ecological and economic development "best-practices" (e.g., holistic watershed management, anadromous fish re-introduction, flow and function, ecosystem services, affordable housing quotas, "Smart" growth, etc.). The research recommends that environmental managers, planners, and local politicians and decision-makers give equal consideration to the socio-cultural, political, economic, and ecological factors surrounding urban rivers, and the diversity of meanings that their "restoration" conjures, in order to make strides towards ethical environmental restoration and management practices that are socially, as well as environmentally, sustainable.