One of the lesser known sources for military records is the Indian War Series. The people that served against the Indians from 1817 to 1898. This was a very common form of service in Northwest Ohio in the early years prior to the movement of the Indians from the area.
This series is indexed by surname and is stored at the National Archives in the Index to Indian Wars Pension Files 1892-1926(T318-twelve rolls). Included in the file is how long the person served, whether they survived the war and if the solider was survived by a widow. They also include places lived. When they were married and to whom. Location where they died and children with birth dates.
As you can see from the overviews on War records there is a lot of valuable genealogical related information that can be gained.