This chapter examines migration patterns around seven Superfund sites, from 1970 to 2000, including periods of remediation. It shows a wide range of changing demographic patterns at the various sites but few definitive patterns across sites. It appears that there is little evidence of groups “coming to the nuisance” in these data. The discussion suggests that one possible reason for this finding is that households may have had different perceptions about the environmental hazards of the sites, and these perceptions may have changed over time in unpredictable ways. For instance, the sites may be perceived to be improving if they are remediated, or, alternatively, the sites may be permanently stigmatized.