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The Pleistocene Epoch was characterized by extensive glacier systems in numerous mountain ranges around the world. Mapping glacial landforms and deposits over many decades of prior work has afforded reconstructions of mountain glaciers, chiefly during the last Pleistocene glaciation and subsequent deglaciation. The availability of high-resolution satellite imagery, digital terrain models, and numerical chronologies of glacial deposits and landforms provides opportunities for mapping paleoglacier outlines and reconstructing ice thickness and volume during specific periods across glaciated regions at different spatial scales. Most paleoglacier reconstructions require outlines corresponding to a specific valley and terminus. However, various formats of digital paleoglacier outlines exist in the literature, some of which encompass entire glacier complexes or ice caps without differentiating between individual valleys and outlet glaciers. Also, unlike inventories of present-day glaciers such as the Randolph Glacier Inventory, digitized paleoglacier outlines lack standardized attributes. In this study, we developed an ArcGIS toolbox to subdivide paleoglacier outlines into individual polygons constrained within watershed boundaries (drainage basins) and to derive a consistent set of attributes related to the geometry, topography, and ice thickness of paleoglaciers. We demonstrate the applications of this toolbox in glaciated mountain areas in Costa Rica, the western U.S., and the central Tibetan Plateau. Although some manual adjustments are still necessary, this toolbox provides an efficient means to standardize the format and derive attributes for paleoglacier outlines. Our proposed framework and newly developed ArcGIS toolbox for standardizing paleoglacier outline formats and attributes improve the value, accuracy, and utility of paleoglacier mapping and paleoclimate reconstruction, and facilitate consistency and comparability among model simulations of glacier and climate changes from the past to present and into the future.