Family breakup is an important event in the life history of black bears (Ursus americanus Pallas), marking the initial dispersal and home range construction of yearling bears, and perhaps marking the timing of estrus and breeding opportunities for adult females. We monitored 6 black bear family groups with 12 yearlings (6M:6F) to determine the timing of family breakup; we intensely monitored 3 of the family groups to document home range establishment and movements by 5 yearling bears (2M:3F) following separation from their mothers. We calculated date of family breakup using 2 separate techniques as 28 May and 2 June, which occurred before peak dates of estrus. We detected 1 reassociation between a mother and her yearling offspring. Following family breakup, female yearlings (n = 3) remained within or near their mothers' home range while yearling males (n = 2) eventually dispersed. All yearlings (n = 5) shared > 50% of post-breakup home range with their mothers.