Isabelle Glacier is an alpine glacier in Colorado’s Roosevelt National Forest between Apache Peak and Shoshoni Peak, just east of the Continental Divide and opposite Fair Glacier. It is the source of the South Saint Vrain Creek and lies within a compact high-mountain landscape shaped by ice and headwater streams. Its location among nearby peaks and beside the divide makes it a notable part of this alpine setting. The glacier is accessible by trail on an 8.4-mile round-trip hike from the trailhead.