Lathrop Glacier was a glacier in Oregon on the steep northeast slope of Mount Thielsen, high in the Cascade Range. Lying generally above 8,500 feet, it was known as the southernmost glacier in the state. It consisted of two small bodies of ice and was first identified in 1966. In August 2020, the Oregon Glaciers Institute reported that it had disappeared, bringing an end to what had once been Oregon’s southernmost glacier.