Welcome Aboard. Were you in Gettysburg yesterday (July 9th? )I was,for the first time in almost a year.
Anyway..to the best of my poor knowledege the militia infantry would have been composed of men,either too old,too young,or not physically able to be in the more strenous volunteer regiments.
Speculation: Maybe a militia unit commanders would have been authorized by their state's
governor or something.
Whereas the volunteer regiments commanders would have been authorized by the President and Congress.
VS..etc
