All players must be at least 55 years of age by the first day of competition. The 144-player field is selected as follows (if qualified applicant received by deadline): (A) Past Senior champions since 2000; (B) Low 80 scorers from the 2017 championship; (C) 70-over champion from 2017 Championship; (D) Through an 18-hole qualifying round from the remaining pool of entrants held August 24 at The Bluffs GC beginning at 8 a.m. If total number of entries received does not exceed 144, no qualifying event will be held. The championship has three divisions: Championship, in which all players who enter will play a golf course from the longest set of tees and the overall SDGA champion will come from this division; Rushmore, in which all players who enter this division will play a golf course set up between 5600 and 5850 yards; and Oahe Division, in which all players who enter will play between 4800 and 5500 yards. All three divisions will be pre-flighted by handicap index. The 70-over Champion will be crowned in the Championship Division only. In the event of a tie for 70-over, the winner will be determined by a scorecard playoff. Plaques will be awarded to the overall champion and runner-up in each of the Rushmore and Oahe divisions.