This data release includes laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) U-Pb zircon geochronology data from four samples collected from syn- and post-Columbia River Basalt Group strata. Samples were collected from within alluvial fan strata and gravel-mantled hillslopes. Sample 16MANC2-01 was collected from an excavation into rounded fluvial gravel deposits along the Manastash Ridge. The unit collected includes Cascadian derived volcanic clasts and is interpreted as an inset terrace of fluvial strata deposited on the Manastash Ridge. Sample 16MANC1-06 is a rhyodacitic boulder collected on a nearby exposure of gravel mantled hillslopes along Manastash Ridge. Sample 16MRF01 was collected from a tephra deposited within alluvial fan strata along the Manastash Ridge range front. Sample 16MRF03 was collected from cross-bedded strata exposed along irrigation canals along he Manastash Ridge range front.