I referred to four sources for information about the First Iowa Cavalry at Osceola, Missouri.

In Frederick Dyer's three-volume work "A Compendium of the War of the Rebellion" the thumbnail history of the 1st Iowa Cavalry indicates that the regiment had some troops stationed at Osceola between March and September 1862.

I checked the Union army monthly troop dispostions given in the 128-volume work generally called "Official Records" commonly found in larger libraries. There were no monthly returns that included numbers of soldiers given for Osceola. I suppose those companies of the 1st were busy with patrols while they were there and may have lacked good clerks to keep such records. The year 1862 was crazy in Missouri and not as many records were created and survived as in following years of the war.

I had better luck with Broadfoot Publishing Company's "Supplement to the 'O.R.,'" especially the part 2 Record of Events which are itineraries of most Union and Confederate units. The records for the 1st Iowa Cavalry are in volume 19 in the set of about 100 volumes published within the last few years. This set is usually found in college libraries and the larger public libraries. This tells me that Company D was stationed in Osceola by or during March 1862;
Companies B and K were garrisoned there by or during April 1862;
Companies B, C, and F were stationed there by or during May 1862;
Companies B, C, and F were garrisoned there by or during June 1862;
Companies C and H were stationed there by or during July 1862;
the troops of the 1st that had been garrisoned at Osceola were moved to Clinton, Henry County and arrived there by August 8, 1862. This marked the end of the garrisoning of men of this regiment at Osceola. This information I found in the regimental records. The individual company records follow in this text and should bear out what I wrote above. This source does not give number of troops at each station.

A source you may wish to consult (but also does not give numbers of troops at each station) is the regimental surgeon's history of the unit written in 1890. This is Charles H. Lothrop, M.D. "A History of the First Regiment Iowa Cavalry Veteran Volunteers" published in Lyons, Iowa by Beers and Eaton, Printers in the "Mirror" Office. The part of this book that addresses the period of March through August 1862 is on pages 60 through 79. You may be able to view a copy via Interlibrary Loan through your local library, but if a holding library would rather not send it there, perhaps they could photocopy those pages for you for a slight fee.

Osceola was important as a port on the Osage River which was navigatable all the way from its mouth not far from the capital of Jefferson City all the way west to Osceola and perhaps a little ways further west toward the Kansas line.

The protection of county records was important to the provisional government of Missouri during the war. When they created the Enrolled Missouri Militia during the summer and early autumn of 1862 they provided that the various militia units would secure and store their firearms at some government building, usually the courthouse, and keep some members of these units on guard there. This practice lasted from fall of 1862 through March 1865 when this "grassroots" militia was disbanded with the return of civil law and peace in Missouri.

I hope this helps your quest.

Bruce Nichols