The distributions of wastewater-derived quaternary ammonium compounds (QACs) were determined in surficial sediments (n = 47) collected from the urbanized lower Hudson River basin. The most abundant class of QACs were dialkyldimethylammonium compounds (DADMACs, with C8 to C18 carbon chain lengths; median Î£DADMAC = 26 Î¼g/g), followed by benzylalkyldimethylammonium compounds (BAC, C12âˆ’C18; 1.5 Î¼g/g), and alkyltrimethylammonium compounds (ATMAC, primarily C16 and C18; 0.52 Î¼g/g). The concentrations of total QACs are higher than those of other conventional organic contaminants determined on the same samples (e.g., median Î£PAH level of 2.1 Î¼g/g). Comparatively high concentrations, correlations with sewage derived contaminants, and the relatively constant compositions of QACs observed over large areas suggest that many sediment-sorbed QACs can be relatively persistent in receiving waters. Unusually large concentration-dependent sorption is considered as a mechanism that likely affects persistence of these intrinsically biodegradable chemicals under field conditions. There has been comparatively little field-based research on these classes of cationic surfactants; given the levels of QACs observed here, it is suggested that further investigation is warranted.