Arctic glaciers that flow into the ocean are changing rapidly due to climate warming. The grounding line, where these glaciers transition from land to ocean, is critical to their stability. We examined Milne Glacier in the Canadian High Arctic using satellite, field, and modelled data. Our study shows how changes in ice flow and ice bending near the grounding line affect satellite-based mapping of this area and documents a newly discovered grounding-line retreat associated with subglacial ridges.