A general lack of capital on American Indian reservations has been identified as a key hindrance to economic development in Indian country. Research on access to credit on reservations is scarce, largely due to lack of data. This paper draws on a unique large-scale individual-level consumer credit database to explore the determinants of credit on American Indian reservations. Using the Federal Reserve Bank of New York/Equifax Consumer Credit Panel (CCP), we combine individual-level data on credit usage with block level Census data on socio-economic and demographic variables. We document differences in credit usage patterns between individuals on reservations and those in nearby areas and examine possible legal and institutional causes of these differences. For example, we modify existing models of credit or liquidity constraints for use with the CCP, to assess whether these constraints appear more or less binding on reservations. With regard to causal factors, we research the effect of the land tenure differences (the extent of fee simple versus trust land), which directly affect access to mortgage credit and, by limiting home equity accumulation, may affect usage of other forms of credit as well. Similarly, we explore the effects on credit usage of differences in tribal jurisdiction over civil and criminal cases (which varies among reservations due to PL280 and subsequent laws) and differences in the proximity of lenders (e.g., banks, credit unions, and community development financial institutions).