Many alcoves on Mars resemble glacial cirques on Earth. While some contain glacier-like forms, many do not, and they have never been studied at a large scale. We mapped ~2,000 alcoves in Deuteronilus Mensae and identified 435 as "cirque-like."  These show geomorphic signs of past glaciation and mainly face south–southeast, implying ice accumulation during high obliquity. Further research is needed to confirm the style of glaciation as either warm-based or cold-based.