North American flying squirrels (Glaucomys spp.) are social species that communally den and exhibit home range overlap. However, observations on home range overlap tend to come from live-trapped individuals and it is unknown whether overlap occurs among individuals belonging to the same social network. Since flying squirrels communally den with familiar individuals, their use of artificial nest boxes allows for the radio-collaring and tracking of squirrels within the same social network. We captured and radio-collared northern flying squirrels (G. sabrinus Shaw) found communally denning in nest boxes in the Appalachian Mountains in the eastern United States. We tracked squirrels captured from the same nest box (i.e., nest box groups) to determine home range overlap and subsequent den sharing between familiar individuals within those nest box groups. We found that amount of home range overlap did not differ between male–male, male–female, and female–female dyads, indicating that non-reproductive females and scrotal males are not territorial at the 95% or 50% home range level. Regardless of sex, all dyads had a significantly higher probability of home range overlap (PHR) at the 95% than the 50% home range level (i.e., overlap between squirrels decreases in core areas of their home range). We also found flying squirrels subsequently denned with familiar individuals during 20.9% of occasions post-collaring. Our study provides important information for understanding space use within flying squirrel social networks. Further work should be conducted to determine space use between familiar individuals including seasonal shifts in space use, degree of individual relatedness, and potential territoriality in females denning with young up to and following juvenile dispersal.