This dataset contains strontium:calcium (Sr:Ca) of water and fin ray samples of native fish to evaluate upstream fish passage through a navigation lock in the Des Plaines River (i.e., Brandon Road Lock and Dam). Fin ray samples from several native fish taxon (catostomids, ictalurids, centrarchids, and lepisosteids) were collected in two river reaches downstream of Brandon Roads Lock and Dam (BRLD) and in a river reach upstream of BRLD. Strontium:calcium derived from microchemistry analyses of fin ray materials from a laser ablation transect is included as both edge values and entire transect (i.e., core to edge). Fin ray edge Sr:Ca of fish sampled from the Des Plaines River upstream of BRLD and in the Illinois and Kankakee rivers (downstream of BRLD) was used to estimate ranges of river-specific fin ray Sr:Ca for each taxon and make comparisons among taxon and river reaches. These ranges were compared to Sr:Ca data along a transect from fin ray core to edge to infer environmental history of individual fish captured upstream from BRLD to determine if a fish’s record of fin ray Sr:Ca contained evidence of the fish having previously been in either the Illinois or Kankakee rivers. This allowed estimation of the proportion of fish that had passed upstream through BRLD. This dataset contains 5 csv files.