The Hadeshorn is a fictional lake from the Shannara series by Terry Brooks. The Hadeshorn sits at the center of the bowl of the Valley of Shale. It is a broad, opaque and strangely still. It's flat surface glimmers with some inner radiance as if something pulses within its depths. So still and flat, that it is like glass and reflects the image of the night sky. The Hadeshorn's waters are poison to the living. In the book The Wishsong of Shannara, Allanon dips the Sword of Leah in the waters of the Hadeshorn and the Sword acquires Magical Properties.