This study considers the rise of girls' summer camps in late-nineteenth- and early-twentieth-century New York State as evidence of broader shifts in American girlhood. The first section traces the historiography of girlhood. Paris then explores how a growing number of girls came to attend camps, establishing semiautonomous and temporary communities away from their parents, and considers how factors other than gender enhanced or limited girls' camping opportunities. The final two sections investigate how girls at camp learned and performed gender and age hierarchies, particularly through ritualized camp activities. Camps, Paris proposes, speak eloquently to the central place of recreation in girls' social inculcation, and about girlhood as a social identity that is learned, practiced, and sometimes resisted. Histories of girlhood, meanwhile, help us reenvision women's history as meaningfully marked by age-bound transitions.