The toughest course in the Chicago-Naperville, IL-IN-WI combined area is Rich Harvest Farms Golf Course, at slope 155 — ahead of Course 4 Dubsdread at Cog Hill Golf and Country Club at slope 153 and Butler National Golf Club at slope 152.

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 highest USGA course rating published for any of the men’s tee sets — the score a scratch golfer is expected to shoot. Men’s ratings only, for the same reason as slope: the men’s and women’s ratings of one tee are different measurements. It measures difficulty and nothing else; it is not a quality score and never orders these pages by how good a course is.

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.

The year the course opened, as published. Ranked oldest first. An opening year is not a design credit and not a renovation date — a course that opened in 1921 and was rebuilt in 1998 still opened in 1921.

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.