Spatial and temporal variations in the age structure of Arctic sea ice are investigated using a new reverse-chronology algorithm that tracks ice-covered pixels to their location and date of origin based on ice motion and concentration data. The Beaufort Gyre tends to harbor the oldest (>10 years old) sea ice in the western Arctic while direct ice advection pathways toward the Transpolar Drift Stream maintain relatively young (≤5 years) ice in the eastern Arctic. Persistent net losses (−4.2% yr⁻¹) in extent of ice >10 years old (10+ year age class) were observed during 1989–2003. Since the mid-1990s, losses to the 10+ year age class lacked compensation by recruitment due to a prior depletion of all mature (6–10 year) age classes. Survival of the 1994 and 1996–1998 sea ice generations reestablished most mature age classes, and thereby the potential to increase extent of the 10+ year age class during the mid-2000s.