In recent years, a range of grassroots interventions have claimed and shaped the use of urban space. Community gardens, unsanctioned public art, temporary crosswalks, miniature lending libraries—these projects and more have been termed “guerrilla urbanism,” “tactical urbanism,” or “insurgent uses of public space.” I choose the term “DIY” or “Do-It- Yourself” urbanism to describe these phenomena in order to emphasize their bottom-up and often ad hoc nature. Accomplishing a variety of aims and existing on a fluid spectrum of legality, DIY urbanist interventions share in common an orientation toward community engagement in changing the use of common urban space.

This Article is the first to examine the trend from a legal perspective. Because many DIY urbanist interventions are at least initially illegal, they raise thorny issues of law and legitimacy. This Article first situates DIY urbanism in the context of other contemporary trends in urban development, then tackles questions of legitimacy, legality, and democracy that these projects raise. DIY urbanist actions, even when illegal, strengthen civic values, enhance community, and may serve to remedy deficits in existing democratic processes. Ultimately, the acceptance of DIY urbanist actions into the mainstream canon of urban development tools reflects the inherent flexibility in property law and other legal regimes that have developed to protect the enduring values of community despite shifting societal circumstances.