The Laurentide Ice Sheet was a large ice sheet that covered much of North America during the last ice age, reaching its maximum extent around 21,000 years ago. It was named after the Laurentian region of Canada where evidence of its existence was first discovered. The ice sheet played a significant role in shaping the landscape of North America, carving out valleys, fjords, and lakes as it advanced and retreated. Scientists study the Laurentide Ice Sheet to better understand past climate conditions, glacial dynamics, and the effects of ice sheets on the Earth's surface.