Although someone may prove me wrong, I lived in that area of NW Ohio for 40 years, and I am unaware of any caves in that area. The nearest caves I am aware of are east of Toledo, eg.. Seneca Caverns. Northwest Ohio is seriously flat farmland.
As to the "underground railroad" although there were some literally underground hiding places, the term "underground railroad" was more about an series of safe houses and trails/routes to take north through Michigan and into Canada. That being said, there are some homes in NW Ohio that were part of the "underground railroad" safe house system, that may have had root cellars or storm cellars used as hiding places.
RTH