Iowa’s oldest trail (technically) is a route established in 1804 shortly after the Louisiana Purchase by famed explorers Meriwether Lewis & William Clark explored the western portion of the continent.
The 212 mile Lewis & Clark Trail is in it’s next phase of development in western Iowa. The route meanders through five counties from Sioux City to Hamburg. It is mostly on-road trail with separated trail through Sioux City and Council Bluffs.
The elevation profile is interesting because you could draw a straight line from Sioux City at 1,100′ to Hamburg at 936′ — it is just a gradual downhill that could be easily ridden in 3 or 4 days. The exception to the gradual downhill is the mini-mountain ranges of the Loess Hills the provide a couple of steep climbs for about 10 miles of each day of the 4 day ride.