The first 5.5 miles are a steep downhill - dropping ~200 feet/mile. The middle 13 miles around Clear Lake and past Rimrock Lake are mostly flat. This section does include a 180 foot hill near mile 12.
The last seven miles through the Rimrock tunnel and along the Tieton River area gentle downhill grade.
The course has a net elevation loss of approximately 2,000 feet. The start is at 4,300 feet and finishes at 2,200 feet.