New detrital zircon geochronologic data from the Straight Cliffs Formation of southern Utah provide insight into the controls on stratigraphic architecture of the Western Interior Basin during Turonian-early Campanian time. Detrital zircon ages (N = 40, n = 3650) derived from linked fl uvial and shallow-marine depositional systems of the Kaiparowits Plateau indicate the majority of zircons in fl uvial strata were derived from the Mogollon Highlands (1.25-1.90 Ga, 67% of fl uvial zircons), with subordinate contributions delivered from the Sevier fold-andthrust belt (265-1250 Ma, 17%) and Cordilleran magmatic sources (81-265 Ma, 16%). Integration of these data with fl uvial facies distributions, petrography, clast counts, and evidence of magmatic arc sources from the Mohave region of California implies the presence of a northeast-fl owing, axial fl uvial system. This system was fed by rivers draining the Mogollon Highlands to the south and by transverse drainages from the Sevier fold-and-thrust belt to the west. Compared to the fl uvial deposits, shallow-marine sandstones have a greater proportion of Sevier fold-and-thrust belt-derived zircons (42%), which were delivered via longshore currents from the north. Shallow-marine samples also contain less Mogollon input (44%) compared to contemporaneous fl uvial systems, and similar input from the magmatic arc (14%). Although Proterozoic zircons associated with the Mogollon Highlands are also present in the Sevier fold-and-thrust belt, several lines of evidence argue for a distinct southerly source for the Straight Cliffs Formation. These include (1) moderate proportions of feldspar and angular quartz grains in fl uvial sandstones, which favor a felsic intrusive source, and (2) prominent 1.4 and 1.7 Ga zircon populations. The 1.4 and 1.7 Ga peaks are the only dominant Proterozoic peaks in samples from the Straight Cliffs Formation, whereas samples derived more directly from the Sevier fold-and-thrust belt tend to have a broader distribution of Proterozoic age peaks. Up-section architectural trends in the Straight Cliffs Formation are linked to trends in detrital zircon geochronologic data, underscoring the likelihood of common drivers and controls. The axial system depositing Straight Cliffs fl uvial strata was primarily fed by drainages originating in the Mogollon Highlands during a pulse of tectonic activity in the Maria fold-and-thrust belt and generally high subsidence rates in the foreland basin (Turonian-Santonian). Over time, activation of the Paxton duplex in the Sevier fold-and-thrust belt (early Campanian) exhumed proximal foreland basin strata and enabled drainage systems from the Sevier fold-and-thrust belt to feed into the basin more prominently. The results presented here underscore the potential signifi cance of axial fl uvial systems and their complex interplay with transverse drainage networks in foreland basins.