Thráin can refer to: Thráin, a barrow-wight from the Norse legend Hrómundar saga Gripssonar Thráin I or Thráin the Old, founder of the Kingdom under the Mountain in Tolkien's Middle-earth Thráin II, father of Thorin Oakenshield in Tolkien's Middle-earth
People "Thráin" is also a transliteration of the Icelandic name "Þráinn" (also rendered as "Thrainn" in some cases). This may refer to: Þráinn Bertelsson an Icelandic film director, writer, politician, journalist and newspaper editor Þráinn Hjálmarsson an Icelandic composer. Þráinn Orri Jónsson an Icelandic handball player