It begins in Glacier Bay National Park in the Saint Elias Mountains, 7 km (4.3 mi) southwest of Mount Hay, trends east into the Grand Pacific Pass area of British Columbia, and then southeast to the head of Tarr Inlet at Alaska-Canada boundary, 68 miles (109 km) west of Skagway.

Much of the ice margin was then grounded at low tide; the calving section probably reached a water depth of only 30–60 feet (10–20 m).

The eastern portion of Grand Pacific Glacier moved only about 150–180 feet (46–55 m) per year based on GPS measurements made by the Cold Regions Research and Engineering Laboratory (CRREL) in 1998–1999.

It had advanced at a rate of about 60 feet (20 m) per year for the last several decades, but it reached a maximum position when it joined Margerie Glacier around 1992.

Rock debris from landslides and medial moraines cover much of this side of the glacier and extends across almost two-thirds of the ice face.