Okay,get ready for this.
Gregorovitch the wandmaker had The Elder Wand. (Only Jo Rowling knows why. Gelert Grindelwald stole the Elder Wand from Gregorovitch. Dumbledore defeated Grindelwald, thus making him the owner. On the night Dumbledore died, Draco Malfoy disarmed Dumbledore, making him the owner of the Elder Wand.
EXTRA INFO: Voldemort assumed Snape owned the Elder Wand, as he was the one who killed Dumbledore, but when Harry, Ron and Hermione got caught by Snatchers, Harry disarmed Draco, making Harry the owner of the Elder Wand.