SIOUX FALLS, SD (KELO) — The Sioux Falls Sports Authority announced on Monday the dates for this year's Sioux Falls Marathon. A news release says annual races will take place on Sunday, September 21st at Howard Wood Field. Registration opens at 10am this morning. The event features a full marathon, half marathon, and 5k race. A portion of the net proceeds will go towards the Sanford Children's Hospital and the Children's Miracle Network. More information can be found at www.siouxfallsmarathon.com.