Furthermost lift bridge that I know of is the old Snowden Bridge near Bainville. Built in 1913 and last lifted in 1935.

It was originally used as a railroad bridge but a plank roadway was added in 1925 so it could be used for vehicle traffic when no trains were coming. RRY put an official halt to that practice in 1977 and a new dedicated to vehicle traffic was constructed. Unofficially, the bridge continued to be used by vehicles for some time after 1977.
Upriver on the Yellowstone, not too far from the Snowden Bridge there is a RRY bridge that has one span that swings like a gate to allow river traffic to pass. Not sure when that one was last used but I imagine it was shortly before the Garrison Dam closed the river for traffic.