Social scientists have entered the debate over the environmental inequities facing the poor in general, and communities of color in particular. Crucial to their empirical studies is the operational definition of "community" as a unit of analysis. Different operationalizations of community exist, leading to divergent conclusions about the extent of the problem. Earlier research concluded that inequities were national in scope, while later studies found little evidence to support the previous research. This paper examines three general ways in which community has been framed as a geographical unit of analysis in environmental justice research: (1) as a neighborhood (a place of cultural identity); (2) as part of a political jurisdiction (county, city, etc.); and (3) as approximated by data constructs (like zip code areas and census tracts). The paper discusses several theoretical and methodological issues involved in operationally defining an appropriate unit, or units, of analysis for research on environmental inequity.