The persistence of informal and illegal urban settlements in the developing world is commonly contrasted to the relative absence of squatting in the developed world, with some arguing that there are models for resolving the problems of land tenure in the developing world in the history of the US. This comparison gets traction in the literature because American urban historians, for the most part, considerably understate the scope and importance of informal and illegal urban settlements. This situation persists despite a growing body of compelling evidence of widespread urban squatting in the US well into the twentieth century. This chapter argues that there are many potential lessons for US urban history from modern squatter colonies and at least as many unlearned lessons for the reverse as well.