From the clubs website:

Named after the majestic oak tree on the 5th hole of the course, Oak Tree National is located in the scenic 640-acre countryside of Edmond, Oklahoma. Oak Tree National has a long-standing history of excellence and exceptional golf.

In 1974, founders Ernie Vossler and Joe Walser directed Golf Course Architect Pete Dye to build the most challenging golf course in the United States. Oak Tree was the result. Dye calls it the finest inland golf course he has ever built - carefully excluding his seaside gems at Harbour Town, Casa de Campo, TPC Sawgrass, and Long Cove. These courses, along with Oak Tree, have been ranked among GOLF Magazine’s 100 Greatest.

During the 1988 PGA Championship, the pros faced a course with a USGA rating of 76.9 for its par of 71 – the highest course rating in the country at that time. In 2002, the course was updated with redesigned greens, longer distances and additional tees, giving Oak Tree National a new course rating of 79.3. Factoring in Oklahoma’s notorious winds, the course presents an unmatched challenge to even the most serious of golfers.

In 2008, Ed Evans and a group of investors purchased Oak Tree from Don Mathis, who had owned and restored the Club since its bankruptcy in 1994. Evans purchased the Club with a vision to re-establish its glory and notoriety. Naturally, Pete Dye returned to lead the project.