Grace, In the 1860 census I found my Nolans living in McKenney Texas. In July 1861, Robert Nolan 20, enlisted in Company K, 3rd Texas State Trops (also called the 11th). The unit left McKenney in early July and moved to forts Cobb and Arbucle in the Wichitaw Mountains of the Indian Territory. This is only about 100 miles north of McKenney. In late August they received word that funding for their company had run out and they were to be disbanded. In a group they went back to McKenney where they found that a regiment of cavalry was being formed in Dallas a few miles south. The whole company commanded by James W. Throckmorton joined Barton Warren Stones Regiment as Company K, 6th Texas Cavalry. All the men of this company came from McKenney or Dallas. Many had migrated to McKenney from Tennessee. My two Nolans 20 and 19 had left their older brother in Tennessee and probably saught adventure. I found their names living with other famlies in McKenney as laborors. They were with different families, and only when they both transferred to the same company, and later census data was I able to connect them. This search began from finding Robert Nolan's pension request in Florida records. He was living in Florida in 1902 when he died.
Though they were close to the Indian Territory they probably did not come from there. The 27th Regiment did have some Indians, who joined with their Texas friends. The 6th Texas may have had a few Indians, but in general they were typical of the makeup of any Texas Town and had migrated from Tennessee and other States to the east such as Arkansas, Missouri and Mississippi.