We investigated microhabitat selection by Terrapene carolina carolina in a North Carolina mountain wetland. We monitored a total of 21 radio-tagged turtles in 1997 and 1998. Turtles were located at least weekly from mid-May until they entered their overwintering sites. Microhabitat characteristics were quantified at each turtle location and at a corresponding random location < 25 m away. Weather varied during the study: 1998 was much hotter and drier than 1997. Microhabitat did not differ between males and females, except that females selected form locations with greater amounts of exposed soil. Overall, turtles constructed forms in areas that were more humid than the surrounding environment. Box turtles also used habitats with lower surface temperatures and higher humidity levels than the surrounding environment, particularly during hot and dry periods. This likely helped them regulate body temperature and prevent desiccation. During the summer of 1997 and all monitoring seasons in 1998, turtles were located at sites with moderate canopy cover and less understory plant cover than expected. Sites with less understory cover may have greater air circulation than those with more cover, thus allowing turtles to dissipate heat more rapidly. Amounts of woody debris, leaf litter, and canopy cover at turtle locations were similar to those available in the surrounding environment. Our results indicate that the attributes most important for defining the microhabitat of T. carolina (surface temperature, relative humidity, and understory plant cover) are related to thermoregulation and minimizing water loss.