The 6th Militia Regiment was from Desha County, but you are probably looking for the Organization listed on Microcopy 317, Roll #249. While it is called the DESHA COUNTY BATTALION ARKANSAS MILITIA, it is really a home guard unit authorized by the Secession Convention. None of the Militia Regiments or Battalions particpated the Battle of Wilson's Creek. Several Volunteer Companies, orgionally organized as militia, made up the Arkansas State Troops Regiments in the 1st Division (really a brigade) of General N. B. Pearce, at Wilson Creek.

A copy of a letter dated Laconia, (AR) Nov 28, 1861, attached to the roll is addressed to Gov. H.M. Rector, Commander in Chief, Arkansas Militia, b T. C. Fluornoy, Col. C.D.C.M. and it shows that the Court of Desha County, Ark in accordance with an ordinance of the State Convention passed in June 1861, organized the militia of the county according to the following plan: The county was divided into military districts (believed to be 13) and a company ordered to be organized in each district. This was done in July 1861 and all the officers of the battalion were commissioned from the County Court. If the emergency arises, which may require the services of the Desha County Battalion to the field, a call will be promptly responded to.
Roll endorsed,’Compared with original paper No. 3379, filed at Executive Office, Little Rock, Ark.’

The record of each man consists of one reference envelope and one muster card. The muster cards indicates the place of enlistment as Laconia and the date of enlistment as Nov 28, 1861. A military district is also indicated. No rank is indicated except for officers.

I also suggest the following Wikipedia Article:

http://en.wikipedia.org/wiki/Arkansas_Militia_in_the_Civil_War