This paper employs data from a recent national survey to offer an empirical assessment of core theoretical tenets of whiteness studies. Using survey items developed explicitly for this purpose, we analyze three specific propositions relating to whites' awareness and conception of their own racial status: the invisibility of white identity; the understanding (or lack thereof) of racial privileges; and adherence to individualistic, color-blind ideals. Consistent with whiteness theories, we find that white Americans are less aware of privilege than individuals from racial minority groups and consistently adopt color-blind, individualist ideologies. However, we also find that whites are both more connected to white identity and culture as well as more aware of the advantages of their race than many theoretical discussions suggest. We then combine these results to estimate that 15 percent of white Americans exhibit what we call "categorical whiteness," a consistent and uniform adherence to the theoretical tenets that are the focus of this body of theory. We conclude by suggesting that these findings provide the basis for a more nuanced, contextualized understanding of whiteness as a social phenomenon.