The toughest course in the Springfield-Jacksonville-Lincoln, IL combined area is Piper Glen Golf Course, at slope 133 — ahead of Illini Golf Course at slope 132 and Edgewood Golf Club at slope 128.

The highest USGA slope rating published for any of the men’s tee sets. Slope rates difficulty for a bogey golfer relative to a scratch golfer — a rated figure issued by the golf association, not an opinion about the course. Men’s ratings only, because a tee is rated separately for men and for women and the two scales do not compare; a course rated only for women is not in the running rather than converted.

The longest tee set the course publishes, in yards from the tips. Compared against every course that publishes a scorecard — length is a measurement, not a verdict on the golf.

Yards between the longest and shortest published tee sets — how far the course moves to fit a different player. Courses publishing a single tee set are not in the running, because one set is an unmeasured spread rather than a narrow one.

Height above sea level at the course’s own published coordinate, sampled from the USGS 3DEP elevation model. THIS IS A FIGURE WE DERIVED, not one the course publishes — anybody can re-query the same public dataset at the same coordinate and get the same number, but no scorecard states it. Because every course carries a coordinate, this is the only board here whose field is nearly the whole database rather than the courses that publish a particular figure. Elevation changes how far a ball carries; it says nothing about whether a course is good.