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We test the research strategy of using youngest U–Pb ages of detrital zircons to constrain the maximum depositional ages of strata containing the zircon grains by comparing U–Pb ages of detrital zircons in 58 samples of Mesozoic sandstone from the Colorado Plateau and adjacent areas with depositional ages known independently from biostratigraphy. Our analysis confirms the validity of the research strategy but indicates that results vary somewhat depending upon how youngest grain age is specified. We use four alternate measures of youngest age which vary from least to most statistically robust as follows: (a) youngest single grain age, (b) youngest graphical age peak controlled by more than one grain age; (c) mean age of the youngest two or more grains that overlap in age at 1σ, (d) mean age of the youngest three or more grains that overlap in age at 2σ. We also calculated the “youngest detrital zircon age …