Diamond X is a 36-hole disc golf course located in Phipps Park, in Billings, Montana. Established in 1997, [1] it is widely regarded as one of the most challenging and most wish-listed courses in the sport. [2] [3] [4] Diamond X is notable for being where Brent Bell set the world record for disc golf's longest ace at 726 feet during the 2002 Big Sky State Games. [5]