Spur Missouri 45 connects Missouri 92 on the west and Missouri 45 on the east, providing a shortcut to the bridge over the Missouri River at Leavenworth, Kansas. This marker is at the eastern end of the spur route.
Missouri state maps indicate another Spur Route 45 in Platte County going into the town of Waldron, but I did not see it marked, at least in the northbound direction, when I traveled along Missouri 45 in September 2005.