Round gobies, Neogobius melanostomus, are an invasive fish detrimental to the stability of aquatic ecosystems, competing for space and resources with native species. While round goby are well-established in Lake Erie, their population size, demographics, and movement in Lake Erie tributaries are unknown. Thus, this study aimed to estimate the population size, understand demographic features, such as size and sex, and assess the movement of round gobies in Elk Creek, a Lake Erie tributary, through a mark and recapture study. For 10 weeks in the Summer of 2024, nine designated 60-m sections in Elk Creek were kick-seined for 30 person minutes to collect round goby. The gobies collected in each section were measured, sexed, and given a section-specific color of a visual implant elastomer (VIE) tag. Recaptured gobies were recorded and retagged with the color of the section in which they were recaptured. Over the 10-week sampling, 1545 gobies were marked, with eight recaptures. Based on the Schnabel Index, the round goby population in Elk Creek is estimated to be 133,188 (95% CI: [78671, 433788]) gobies. There was no significant difference in the size of males and females, but juveniles were significantly smaller than both sexes and the most abundant in mid-June and mid-August. As the summer progressed, fewer gobies were collected overall and within sections. Goby size and sex did not differ significantly over the summer and between sections. Recapture data cannot indicate certain movement patterns, but suggests that significant movement is unlikely. Given this, sections abundant with goby should be targeted consistently for round goby management.