For decades, Philadelphia has ineffectively balanced increasing development pressures with protection of the city's historic resources, resulting in the loss of locally and nationally significant places. To the extent that local preservation efforts have been effective, they have relied heavily on the use of historic districts (roughly seventy percent of all buildings in the Philadelphia Register of Historic Places owe their protection to this mechanism). Nonetheless, nominations of traditional, neighborhood-bound historic districts have been tabled or dismissed by the Philadelphia Historical Commission for over a decade. The impasse stems from misguided perceptions about property values and building maintenance, political pressures (increased by the tradition of "councilmanic prerogative"), and the inability of the Commission to manage large districts with limited staff and resources. Since 2010, the Historical Commission has, however, approved two small districts along a single block or small portion of a street. While this approach may seem less threatening to opponents of large historic districts, the narrow scope of these districts makes them far less effective as preservation tools than their more expansive predecessors. A presently unexplored alternative to nominating part of a street is to use the entire street length as a historic district. In this thesis, I will argue for this approach and, in doing so, aim to underscore the benefits of integrating historic preservation practice with cultural landscape theory. Streets and cultural landscapes provide complementary ways of transcending the artificial boundaries of a neighborhood and understand patterns of movement, changes in architectural style and taste, and transformations in urban form over time. After presenting a literature review, I will show that language set forth by the National Park Service and local city ordinances not only discredits the micro-district methodology but also conflates aesthetic assumptions and value judgments with historical arguments. To test this hypothesis, I consider the significance of Chestnut Street, between 40th Street and 63rd Street as a historic district and an urban cultural landscape. By combining cultural landscape theory with the street's spatial, urban, and social histories, the area of significance includes buildings that would otherwise be undervalued in a traditional architectural survey.