This dissertation combines approaches from cultural landscape analysis, ethnography, and planning history to study the Capital Beltway in Maryland, Virginia, and Washington, D.C. as both a physical artifact and a social institution. Drawing on interviews, survey data, fieldwork, and documentary research, I explore the ways in which the Beltway, its creators and users, and its surrounding natural landscape have affected each other over fifty years. Three research methods underlie this study. First, I introduce an analytical framework for odology, geographer J.B. Jackson’s term for the study of roads, focusing on the beliefs and values roads reveal and create, dynamics of power and access, contributions to normativity, issues of conflict and consensus, and effects on individuals’ lives and identities. Second, I develop and apply a detailed framework model for cultural landscape analysis, building on previous efforts in cultural geography and material culture studies. Third, I draw on and analyze the dynamics and results of a Web survey. The dissertation provides the first detailed discussion of the Capital Beltway's development and construction in Maryland and Virginia, drawing in part on interviews with ten of its original engineers and beginning with an overview of the origins of beltway planning in the United States. It examines the Beltway's effects on individual lives, communities, and the broader metropolitan Washington region, concentrating on conflicts and perceived inequities created by the Beltway's construction, and on both states' efforts to pursue their own agendas and also to redress residents' concerns over the fifty years covered. The study addresses both physical and cognitive manifestations of the Beltway, exploring how the road exists in the minds of the people who use it and how its material and conceptual iterations combine to play an integral role in their lives. It also analyzes how the Beltway serves concurrently as a template through which individuals and groups promote their values and beliefs, as a venue of conflict and community, as a vehicle for the creation of a distinct regional identity, as a site of negotiation between public and private space, and as a site for mediation and compromise in interjurisdictional cooperation.