Belonging in the US involves both assertive processes, ways in which individuals claim American identity, and ascriptive processes, the degree to which one is seen as a national in-group member. US history provides a landscape in which conceptions of national identity often intertwine with how we think about and experience race. To engage the complex nature of belonging in the US, I ask - how does the symbiotic relationship between race and national identity shape processes of belonging? To address this, I use data from a mixed-method study called the Race – Ascription, Assertion, and Contextual Experiences Study (RAACES) that includes survey data among a racially diverse sample of almost 2,000 native-born Americans, supplemented with 94 follow-up interviews. To interrogate belonging, I take three approaches. First, I interrogate the relationship between how one “reads” others racially and ascription of that person as “immigrant” or “American.” Second, I ask what it means to experience challenged Americanness, social interactions in which individuals’ American identity comes into question by others. Using both survey and interview data, I identify racial patterns in Americans’ subjective and objective sense of their own Americanness and then use interview data to further explore the nature of having one’s Americanness challenged. Third, I ask how processes of belonging in the US can be understood through exploring criteria associated with “being American” and to what degree responsibility is contained within immigrants’ locus of control regarding “fitting in” US society. I find that Whiteness pervades processes of belonging in that being perceived as White and ability to identify as White enhances being seen as belonging in the US. Moreover, not only does a non-White identity present obstacles to belonging for persons of color in the US, but the relationship between race and national identity for non-Whites can be contingent on real world events that influence their recognition as American. Thus, the path to belonging for many in the US is not an accomplished or achieved status, but something subject to perpetual (re)negotiation that may include or exclude them from belonging in American society.