The Hays Mountains (86°S155°W) are a large group of mountains and peaks of the Queen Maud Mountains of Antarctica, surmounting the divide between the lower portions of Amundsen Glacier and Scott Glacier and extending from the vicinity of Mount Thorne on the northwest to Mount Dietz on the southeast. They were discovered by Rear Admiral Richard E. Byrd on the South Pole flight of November 28–29, 1929, and mapped in part by the Byrd Antarctic Expedition geological parties to this area in 1929 and 1934. They were named by Byrd for Will H.