This study investigated the effect of geographic location on Severe Early Childhood Caries (S-ECC) in Native American Children three years of age from a Norther Plains Tribal Community. Geographic location of study participants was ascertained by postal district and categorized into geographic regions as well as dental clinic accessibility, defined as dental services present or absent in that district. The association of location category and dental caries (dmfs) was evaluated cross-sectionally at 36 months of age. Descriptive statistics demonstrated differences in dental caries distribution by geographic region and accessibility category. Bivariate analysis of disease by location showed a significant difference in dmfs between 4 geographic regions (p=0.0159) but not between accessibility categories (p=0.0687). Multivariable regression modeling for geographic region demonstrated the unique effect of geographic region on dental caries experience as well as five other key risk factors. Incident Rate Ratios (IRR) were computed for each of the risk factors, including number of erupted teeth (IRR=1.89, p=0.0147), fluoride exposure from tap water (IRR=1.70, p=0.0173), annual family income (IRR=1.58, p=0.0392), maternal DMFS (IRR=1.02, p=0.0040), and Mean Adequacy Ratio (IRR=1.05, p=0.1042). This study demonstrated statistically significant variation in cumulative dental caries experience of Native American children aged 36 months among geographic regions and identified the specific unites of association through multivariate modeling. These findings can be used for local dental caries prevention programs and contribute to a broader understanding of S-ECC among very young Native American children.