While conducting a study of home range and habitat use of the eastern hognose snake (Heterodon platirhinos) in Southern Ontario, we observed both mating and nesting behaviors for this species. Here we describe the active excavation of oviposition sites by H. platirhinos; mating behavior, including multiple copulations of a single female with five males; and philopatry to specific nest sites by multiple individuals in successive years. As our study site is close to the northern limit of this species' range, nest sites may need to be carefully selected to provide a thermal regime warm enough to incubate the eggs. Mean nest temperatures in the field ranged from 23.4 to 26.1 C, while incubation periods ranged from 49 to 63 d.