Hi - Got this from the link below:

http://www.homeschoolblogger.com/military/141970/

On the above blog, you will also fine access to a mini-unit study about the Underground Railroad. 

Here is a listing of known Underground Railroad stops in each state.  Great to use for vacation planning or just day trips around Iowa, perhaps.   These are not all open to the public.  There are 4 listed in Iowa - 2 on the southwestern side of the state, one in Des Moines, and one south of Mt. Pleasant in Salem. 

http://www.cr.nps.gov/nr/travel/underground/states.htm

Interestingly, I checked out the link to the one in Salem and I wasn't much impressed with their write up.  I have been there and there is, indeed, a hidden room under the floor and according to the tour guide, was definitely a stop on the underground railroad, not just possibly as the web site indicated. 

Check out one near you (unless you live up north, then there aren't any listed, sorry).  Nancy