This cache is near the 3rd gate on the road along the east side of the Pemi. You can continue over a modern bridge on a very faint trail all the way to Bristol, but for most people this is the end. This is the site of a covered bridge that connected the folks that lived along the east bank with the larger settlement of Hill on the west bank. You'll see a huge support in the middle of the river complete with steel plates on the upstream side to fend off ice. It's still in great shape. It was probably torn down around 1943 when the Franklin Falls Dam was completed. So it's at least 80 years old and could easily be over 100. There is a cache on the other side so you can achieve some balance by finding both.
Be careful if you look for this cache in October. There are several large fields before you get to the old bridge where pheasants are released on 3 dates in October and hunters flock to the area. Check https://www.wildlife.state.nh.us/hunting/pheasant.html for the exact dates this year. The season runs from October 1st to December 31st; but the action is in October.
The bridge is about 2.5 miles from the first gate. You can drive all the way in October because the 2nd gate will be open for hunters. So there are pros and cons to coming then. I personally don't like to be looking for caches with gunfire in the background. The cache is a handcrafted magnetic holder of a stubby bison tube. Keep your eyes open for bald eagles; I've seen them many times in this area.