Within the Russian Federation there are nearly 200 recognized "nationalities," approximately 130 of which could claim to be "indigenous." However, only 45 peoples are officially recognized as "indigenous small-numbered peoples of the Russian Federation" and thereby qualify for the rights, privileges, and state support earmarked for indigenous peoples. This status is conditioned upon a maximum group size of 50,000. While experts insist that this numerical criterion is provisional and without serious political implications, our fieldwork demonstrates that it has become a social fact that cannot be ignored, especially in light of the 2002 All-Russia Census and the release of its results in 2004. This numerical benchmark forces a dichotomization into small-numbered versus non-small-numbered peoples and creates a peculiar type of identity politics based on ethnic-group size. The "indigenous small-numbered" status is also conditioned upon a set of overlapping but often contradictory residency requirements. Using case studies from southern Siberia and the north of European Russia, we document the dynamic interplay between these dimensions of identity and the opportunities for maneuvering in the competition for the benefits that attach to certain categories. However, indigenous peoples who engage in such identity politics run the risk of becoming "incarcerated" within the confines of those categories.