At the Mountains of Madness is a science fiction-horror novella by American author H. P. Lovecraft.  It has been reproduced in numerous collections.

The story details the events of a disastrous expedition to the Antarctic continent in September 1930, and what was found there by a group of explorers led by the narrator, Dr. William Dyer of Miskatonic University. Throughout the story, Dyer details a series of previously untold events in the hope of deterring another group of explorers who wish to return to the continent.