Scientists use glaciers and their surrounding landscapes to understand the climate of the past. Radiocarbon dating is a technique that measures how much time has passed since the organism died. To reconstruct the history of the growth and retreat of glaciers, we radiocarbon date tundra plants that were killed by glaciers advancing over them during past cold periods. The timing of past glacier changes from “glacier-entombed” plants informs the scientific community about the history of climate change. Our research objective is to use radiocarbon dating of plant samples collected from Østtungerne ice cap in Greenland to identify timing of past glacial advances. We also collected proglacial threshold lake sediments, which provide information about when a glacier advanced or retreated in the past. Our lake sediment data suggest that the glacier was already expanding by 3000 years ago. The moss dates show that the glacier grew in pulses ~1700 (n=2), ~1000 (n=3), and 670 (n=2) years before present (1950). It also may have advanced ~2200, ~1200, and ~500 years ago. This project contributes reconstructions of Greenland’s glacier history, observations that will join a larger database of information used to build understanding of global climate change in the past, present, and future.