Movement behavior and timing of mating vary between populations of snakes. Here I present data on movement and mating behaviors of adult male Crotalus oreganus concolor in southwestern Wyoming and compare the results to other populations. Male C. o. concolor make short, infrequent movements. I found no evidence of migratory behavior or shifts in areas used during the monitoring period. Mating behavior was limited to 5–17 July, shorter in duration than for any other population of C. oreganus. Male snakes located and courted females prior to shedding of the females; however the only successful copulation was between a pair that had recently shed. One instance of male-male combat was observed, during which the larger male displaced the smaller male.