The challenge is to find at least one cache between each elevation marker given. You can have found these caches anywhere in the world, not just Wisconsin.
You will need a total of 17 caches to qualify for this challenge.
Markers:
0 ft and 10 ft
11 ft - 50 ft
51 ft - 100 ft
Every 100 ft marker from 101 ft to 1,000 ft
Every 1000 ft marker from 1,001 ft to 5,000 ft
And one last cache between 5,001ft and 5280 ft
Since there are no mountains or oceans immediately in the area, you will have to be a fairly well traveled cacher. That is the reason for the high difficulty. I have provided a checker below to streamline seeing if you qualify.
Thank you shelrik for allowing me to duplicate this challenge in Wisconsin.