Harbor seal (Phoca vitulina richardii) use of a haulout in Vitus Lake at the terminus of the Bering Glacier (60° 5' N, 143° 30' W) was characterized by conducting 69 aerial surveys over the 2001-2003 period. Harbor seals were observed hauling out only on low, flat icebergs in Vitus Lake, predominantly (80% ± 3%) at the head of Seal River. There was a marked increase in seal abundance in the fall (from <200 to >900 seals), and as seal abundance increased, the average number of seals per iceberg remained relatively constant (10 ± 1 seals/iceberg), while the average number of icebergs occupied increased (from 12 to 48 icebergs in 2002). In 2003 the number of icebergs used was lower, and therefore seal density per berg was higher, than in 2002, suggesting that the availability of suitable ice influences grouping behavior in harbor seals. Diet and genetic studies suggest that harbor seals move into Vitus Lake from stocks in both Southeast Alaska and Prince William Sound in order to forage on local salmon runs. These findings have implications for ongoing efforts to determine appropriate stock structure for management decisions and suggest that the frequency and extent of seasonal movements must be considered when conducting regional population monitoring surveys. As human activity in the Bering Glacier area increases, monitoring and educational efforts should be initiated in order to ensure that harbor seals remain a functioning element of the ecosystem.