The compositional traits of C9-34 n-alkanes were measured in supercritical CO2 extracts from 14 U.S. coals of varied geologic ages and wide thermal maturity range (lignite through low-volatile bituminous). The analysis data exhibit no unique component depletion pattern signatures diagnostic of known types of postgeneration physical, chemical, or microbiological degradation processes that commonly affect crude oil in sedimentary rocks. The C9-34 n-alkanes in Paleocene and Upper Cretaceous age coals exhibit bimodal carbon-number distribution profiles that strongly resemble those of the biogenic n-alkanoic acids present in brown coals. The compositional trait similarities between these n-alkanes and n-alkanoic acids and the covariance of the bulk coal organic matter atomic oxygen-to-carbon (O/C) ratios and carbon-preference index (CPI) values offer tangible evidence for the existence of a genetic linkage between these two series of compounds. Our analysis results indicate that the C2-5 alkanes and C6+ hydrocarbons in coals attain their maximum abundances over the thermal maturity interval from 0.50 to 0.72% R-0, which, in turn, strongly suggests that these two groups of compounds are formed concurrently by similar overall reaction processes during coal maturation. The compositional traits of the C4-5 alkanes and C9-34 n-alkanes in coals appear to uniquely mimic those of the alkane products formed by mineral-catalyzed defunctionalization and cracking of n-alkanoic acids, which suggests that mineral catalysis rather than temperature-controlled thermolysis may be a critical variable controlling the formation and compositional traits of natural gas and C9+ n-alkanes during coal maturation. These mechanistic insights should be useful to those seeking to formulate improved geochemical models for predicting hydrocarbon evolution during coal maturation.