Immigrant-run sexually oriented massage parlors embody the intersection of important planning issues, including inequitable distribution of controversial land uses and economic functions of illicit businesses. We analyzed geocoded data from a ratings website to examine sexually oriented massage parlor clustering in Los Angeles County (LAC) and New York City (NYC). In LAC, clustering occurred in areas with more Asian and Hispanic residents. In NYC, clustering occurred mostly in Manhattan and was negatively associated with household size. Local regulation did not appear to affect clustering. Study findings hold lessons about both more effective regulation and enabling economic development in immigrant populations.