Forgot to mention why I posted.
While looking through some books that I inherited, I opened one that is some kind of historical account of Michigan. Within its pages, there is an account of several groups of militias from Michigan that reported for duty during the Civil War. Each of the militias had a name related to an area and rather than suggesting the numbered division or battalion of a standing army. I'll have to dig it out later and take another look.
There are several flavors of milita under the law. The Militia act covered the unorganized reserve militia. The best description of that that I know of comes from a court case in the 1880's Presser v Illinois.
Here is the best section on the militia
"It is undoubtedly true that all citizens capable of bearing
arms constitute the reserved military force or reserve militia of the United States as well as of the States, and in view of this prerogative of the general government, as well as of its general powers, the States cannot, even laying the constitutional provision in question out of view, prohibit the people from keeping and bearing arms, so as to deprive the United States of their rightful
resource for maintaining the public security, and disable the people from performing their duty to the general government."
Presser v Illinois US Supreme Court 1885
The "constitutional provisions' they discuss are differences between the federal laws on militias and the Illinois laws. The court did not rule on these as they were able to reach an opinion without such a ruling, though they did write an opinion that read like the state was in trouble if challenged with a better case.