In Maine, at mile 450 along the US-Canada border the swath crosses over a 3500+ peak informally known as Monument Mountain. Does this peak have a summit register? When I was up in the area, a ranger I talked to thought there might have been one at one time, but he was unsure of its current status. Having passed over the peak twice, I didn't see anything (not that that's saying anything), but the mountain seemed to have the requisite features for having a register jar on it.