Research on mixed heritage people has often focused on their reported race(s) and what these self-reports may reveal about their racial leanings. In the U.S., people are also asked: “What is this person’s ancestry or ethnic origin?” as a census fill-in-the-blank question. Existing research has analyzed the census data on race and ancestry and has uncovered meanings about ethnicity among White Americans, but little is known about the importance of ancestry in the case of mixed heritage people. In this paper, we draw on our interviews with 68 American-Indian-White, Black-White, and Asian-White mixed heritage people in the U.S. Given that many mixed heritage people’s connections with their disparate ancestries can be hindered by generational distance, lack of cultural contact and exposure, and social rejection, what motivates mixed heritage people to report their disparate ancestries, and how do their ancestry claims relate to their racial identities? How may the differential histories and racialization of groups in the U.S. shape mixed heritage people’s ability and inclination to assert either their White or minority ancestries? We found that mixed heritage individuals who were motivated to assert their ancestry claims did so for two main reasons: First, by claiming a specific ancestry (or ancestries), participants wished to assert a more individualistic sense of self than was typically allowed, given their racial treatment based upon their racial appearance; this could be especially meaningful if those individuals felt a mismatch between their racial assignment by others and their sense of self. Second, a claim to a specific ancestry was a way for individuals to forge connections with family, relatives, or an ancestry group that had not existed before. Overall, while most of our mixed heritage participants reported details of their European ancestries, it was their Black, American Indian, or Asian ancestries that were deemed to be most salient and/or meaningful to who they were.