Roads can have major impacts on wildlife, causing habitat fragmentation and direct mortality from wildlife-vehicle collisions. Therefore, wildlife crossings are often constructed on roads to help promote landscape connectivity and reduce wildlife road mortality. To assess the effectiveness of wildlife crossings over long time periods, it is important to establish baseline usage rates along the highway before the mitigation structures are constructed. In South Texas, wildlife crossings are being built to reduce threats of roads to the endangered ocelot (Leopardus pardalis). However, these crossings benefit a wide variety of species in addition to ocelots. We assessed baseline usage rates of future wildlife crossing structures on Farm-to-Market (FM) 1847 in eastern Cameron County, Texas. Construction of wildlife crossing structures on FM 1847 began in February 2020. We used camera traps set at the locations where the crossing structures will be built to monitor wildlife use of those sites from July 2019 through November 2020. We assessed differences in the medium to large-sized mammal community in the pre- and during-construction periods. We determined the number of individual photographic events, camera trap success rates, and diel activity for individual species and conducted a reciprocal averaging ordination to assess differences in species, sites, and time periods. We detected fewer individuals and fewer species in the during-construction period than the pre-construction period, however species showed similar diel activity in the two periods. Relative species abundances tended to increase along an urban to rural gradient as wildlife crossings became more rural. These results will help establish baseline usage of future wildlife crossing locations on FM 1847 and allow us to assess their effectiveness at reducing road mortality and increasing landscape connectivity.