The author builds upon Michael Schwartz's (1976) concept of "structured ignorance" and draws upon Peter Blau's macrostructural theory of social relations (1977 and 1994). Schwartz argues that individuals make choices and decisions based on limited information, and information that is required to develop an accurate diagnosis of a collective problem is distributed unevenly throughout the social structure. An individual's access to relevant information, therefore, is largely determined by his/her position within that structure. Blau's macrostructural theory of social relations identifies forms of structural differentiation that facilitate and sustain organized racism in the United States. Blau demonstrates that heterogeneity on nominal parameters promotes intergroup contact. Following Schwartz's lead, this article considers the ways in which different patterns of structural differentiation in society can either conceal or reveal information that is required to develop an accurate diagnosis of the problems that confront groups and individuals. The application of the theory of structured ignorance to the development and maintenance of the White supremacy movement and the various groups that comprise it begins with a profile of these groups followed by a brief discussion of theoretical approaches that have been used to explain racial conflict and social movements. The theory of structured ignorance is then applied in analyzing variation in the number of racist organizations in U. S. counties in 1997 and 2000. The primary goal of this analysis is to identify the structural conditions that facilitate racist organizing by providing a context in which the world-view that is constructed within racist organizations reflects what White supremacists observe in their daily social interactions. The central theme of the analysis is how ethnic antagonisms can develop in the absence of intergroup contact. 8 tables, 7 notes, and 123 references