Why give people the impression that it was US Army regular troops?
If it doesn’t make a difference to you, then let people know that it was a Colorado state militia.
My point was that I’m unsure on the practical difference at the time. Were these part-time soldiers on a weekend raid, like we usually think of the milita, a Home Guard, if you will, or were they full-time soldiers just like those fighting back east, only Volunteers instead of Regulars?
If the first, then the distinction between Regulars and militia is significant. If the second, then IMO it is not and the US Army is fully responsible.
At the time, something over 95% of Union army were Volunteers.
The unit most certainly wasn’t a State Militia, since CO didn’t become a State till 1876. Hence the state nickname, the Centennial State. :)