Indoor radon is a major preventable health problem and determination of risk factors that contribute to gas accumulation in homes would help in remediation efforts. This paper examines four specific radon risk factors using geoinformatics techniques to evaluate contributions to residential radon vulnerability. Statistical analysis of 205 radon samples collected between 2004–2005 in Warren County Kentucky determined that 1) homes with basements and 2) homes built before 1977 have a higher probability for radon levels above the EPA action level of 4 pCi/l than any other type of structure analyzed. Homes above 140 square meters (1500 square feet) in size did not have a significantly higher chance of having a radon level above 4 pCi/l than did homes below 140 square meters in area. Also, the depth to the Chattanooga Shale, a suspected source of radon, did not have a significant impact on the measured levels. It is likely that another source of uranium, soil or limestone, contributes to radon loading in homes.