This essay points to residential location as an important source of group interest, alongside the more familiar factors of race, class, and gender. This group interest is especially strong among people living in or dependent upon a particular city. This phenomenon is illustrated here through a variant of central-place theory applied to the history of South Africa and the Argentine pampa from the mid-eighteenth to the late nineteenth century, with particular attention to the play of rivalries between cities and conflict between cities and their hinterlands.