Creigiau Gleision is a mountain in Snowdonia, Wales, near Capel Curig. It is the easternmost of the high Carneddau and is separated from the others by Llyn Cowlyd. Directly across this reservoir from Creigiau Gleision is Pen Llithrig y Wrach. To the north-east it runs into the broad ridge of Cefn Cyfarwydd.
In fact the mountain has three peaks, hence perhaps its plural name. The most southerly peak is the highest, at 678m, and the O.S. map also marks the northerly peak (some ½ mile distant) at 634m. Between these two lie a middle peak, of a height between the outer two, but cairnless and unmarked on the O.S. map.
Colin Adams, author, has reached the summit of Creigiau Gleision over 450 times. On many occasions he has encountered a ghost there who has spoken with him, and although he makes no reference to this in his book, he has written about it online in "The Angry Corrie" in 1999.