Concentration of hafnium in detrital zircons is a reliable indicator of petrogenetic relationships between sandstones. Frequency distributions of hafnium composition are statistically similar for zircons in sandstone units that were derived from the same proximate source. Previous studies, using optical and cathodoluminescence petrology, have shown that the upper Jackfork Sandstone (southern Ouachita Mountains, Arkansas) and the Parkwood Formation (Black Warrior Basin, Alabama) were derived from the same proximate source area. In this study, analysis of Hf in 1,595 detrital zircons revealed a statistically insignificant difference between the upper Jackfork and the Parkwood, corroborating a common proximate source for the two units. In contrast, frequency distributions of Hf content were significantly different in zircons from three petrogenetically unrelated sandstones.