45 X 90
Located near the town of Poniatowski, Wisconsin (a rural farm community about 30 minutes outside Wausau), is a wooden geographical (not geological, as the sign reads) marker near where the 45th Latitude and 90th Longitude intersect.
"This spot in section 14, in the Town of Rietbrock Marathon County is the exact center of the Northern half of the Western Hemisphere. It is here that the 90th Meridian of Longitude bisects the 45th Parallel of Latitude, meaning it is exactly halfway between the North Pole and the Equator and is a quarter of the way around Earth from Greenwich, England. ~Marathon County Park Commission"
For more information, read this beautifully written and researched post on AtlasObscura.com.
While the "true" intersection is located in the middle of the nearby farm field, there is a small parking lot where you can stop to take a few souvenir photos. If you geocache, this is the site of an easy ghost cache (meaning, you only need a photo to log the find). While we did stop by the Wausau Visitor's Center to sign the official "45X90 Club" log book, we did enjoy many of the other family-friendly attractions in the area (look for a post on this soon).
And, for what it's worth, there are three other 45X90 spots on earth, two of which are in the Pacific and Indian Oceans and the third in rural China—proving, it is truly possible to dig a hole and end up in China, if you really wanted to!