Property law plays a crucial role in the ability of groups, especially ones composed of geographically-adjacent members, to establish and maintain significant forms of "community" around a shared social, economic, or ideological interest. Property may also, however, have the opposite effect of undermining or even destroying communities, particularly those that rely on fragile modes of cooperation. This Article identifies three major types of territorial communities: (1) Intentional Communities—close-knit groups that initially organize around a consolidating non-instrumental idea (such as cooperative Kibbutzim or religious communes) and employ sweeping internal norms to validate their communality. (2) Planned Communities — comprised mostly of residential developments of homeowners associations, which rely on a formal set of conditions, covenants, and restrictions incorporated in the association’s governing documents. (3) Spontaneous Communities — clusters of initially unorganized neighbors who succeed in cooperating and coordinating over time. The evolvement of such organizations may be essential to the creation of an interpersonal "social capital" and to a physical and functional improvement of the community’s surroundings. For each one of these types of communities, property law plays a very different role. Thus, while Intentional Communities do not strictly hinge upon the existence of a supportive property system to flourish, Planned Communities cannot be conceived without the security of an overt, formal, state-backed regime, and Spontaneous Communities may often need property law’s affirmative backing (providing what I term "Property Tailwind") to thrive and enjoy the social and economic benefits of sustainable collective action.