The Western Historical Manuscript Collection at the University of Missouri-Columbia has several letters written by Henry C. Crawford and William H. Crawford. According to the WHMC, the Crawfords served in the Third Missouri State Militia Cavalry.

The letters make it clear that the Crawfords took part in Union operations in Benton, Madison, and Washington counties in northwest Arkansas in October 1862 as part of Schofield's Army of the Frontier. So far I have not been able to locate any documentation that the Third Missouri State Militia Cavalry was part of the Army of the Frontier.

So, two related questions:

(1) Was the Third Missouri State Militia Cavalry part of the Army of the Frontier at that time?

(2) If not, then the Crawfords obviously were in another Union unit. Which one?

Any help will be much appreciated. Thanks in advance.