For decades it was said that the exact midpoint between the North Pole and the equator was the Wyoming/Montana state line, where parking is for the Boiling River. Then, twelve years ago, it was recalculated to be ~1 kilometre north of the state line, though the current sign is .33 km. further north than the actual gps located spot for the sake of safety at a turnout. Oops.

You're halfway to the northpole! How can you pass this photo stop up. The stop is at GPS coords: 45.003354, -110.692292

We were hoping for the photo op here but they were working on the area and the sign was nowhere to be found.

Located 2.4 miles (3.9k) beyond the north entrance station to Yellowstone National Park, which is near Gardiner, MT, at the Montana-Wyoming border, there is a small sign at a pullout on the west side of the road noting the 45th Parallel. While this is not a spectacular sight, it is worth a quick stop for a photo or two and couple moments to take in the scene and contemplate being halfway between the Equator and the North Pole.

Along the road between Mammoth Hot Springs and the Roosevelt Arch is a National Park sign marking the 45th Parallel, the halfway point between the Equator and the North Pole. The 45th Parallel runs across the continental United States and I'm not sure what is so special about the Parallel at this location, but if you are passing by, stop and take a picture of yourself with the sign.