Six gasoline samples were collected from around the U.S. in Autumn 2004. The samples included regular and premium grade fuels, conventional and reformulated gasolines, high and low elevation samples, and fuel subject to state regulations (especially bans of methyl tert-butyl ether). A detailed hydrocarbon analysis was performed on each sample resulting in data set of approximately 300 chemicals per sample. Comparisons were made between several significant individual parameters. The results showed that benzene was, as required by the Clean Air Act, below 1 percent in areas that require reformulated gasoline (RFG). Higher benzene levels were found in some samples outside these areas. Methyl tert-butyl ether (MTBE) was found in use in RFG areas where there were no state bans in place. Where MTBE was banned, ethanol was found as the replacement oxygenate. Statistical analyses were performed on the entire suite of reported chemicals. These analyses were used to determine which gasolines were similar and if characteristics of the gasolines (conventional/reformulated, grade, elevation, and MTBE ban status) could be used to segregate the fuels into a decision tree. The statistical analyses showed that the gasolines were separable by these factors, but that differences due to state regulations or variability in the fuels make certain gasolines dissimilar from gasolines of similar characteristics. This feature was evident in the premium grade gasolines, presumably because refiners use different approaches to boost the fuels octane number. Estimated solubilities and vapor pressures of the majority of the chemicals were used to predict the effective solubilities and gas phase concentrations of each chemical in a gasoline. Three types of low elevation, regular grade gasolines were included: conventional, MTBE-RFG and ethanol RFG. Pair-wise comparisons of these fuels showed predicted shifts in aqueous and gas phase concentrations.