My Mapsource software shows "Cockran" Cemetery on the south side of Clear Boggy and west of the present road south from Frisco. Per Muriel Wright & Leroy Fisher, Cobert's Institute in Perryville moved west in about 1858 and was also located on the south side of Clear Boggy and east of the road coming south from Frisco. One Chronicles article says 'Colbert's' was the Chickasaw Manual Labor Academy and was different than Collin's Institite that was established later. Per a couple of different articles in the Chronicles, Colbert's Institute moved into the Chickasaw Nation near present Frisco/Stonewall prior to the war.
I don't see "Cochran's Academy" (sometimes just shown as "Academy") on any pre-1860 maps. This doesn't prove it didn't exist at that time, of course. It is on most maps from 1867 to about 1890 and shown on upper Middle (Muddy) Boggy in the Choctaw Nation. Until Oklahoma was surveyed in the 1890s, none of the maps show the correct locations of Boggy and Middle Boggy.
In the Clarksville TX newspaper in 1862 is a letter from "A Soldier in the 29th" [29th TX Cavalry] who describes their march from Fort Arbuckle (new), camping at Cochran's on South [Clear] Boggy, the road to Perryville, and up the Texas Road to Camp Butler (on Butler Creek near its mouth on Elk Creek -- near Honey Springs).
This 'Soldier in the 29th' somehow knew they were on South Boggy and describes the march crossing the headwaters of the other 'Boggies' on the way to Perryville. However, post-war maps (1867 and 1869) show Cochran's on Middle Boggy in the Choctaw Nation. This makes me wonder if the battle was at Cochran's on Clear Boggy in the Chickasaw Nation but Phillips thought he was on Middle Boggy in the Choctaw Nation. To carry this line of thinking further, he may have marched 20 miles south to the Blue River which he mistook for South Boggy. I'm not promoting this view, just considering the possibilities.
Anyone reading my posts on the subject knows that: Considering all available evidence (that I have found so far), I find no evidence that Phillips was at or near the Texas Road and therefore never near Perryville, Geary's, present Atoka, or Boggy Depot.
I cannot find the origin of the belief that the battle was near present Atoka. Perhaps it is based on the assumption that Phillips would have taken a direct route down the Texas Road from Ft Gibson which, per the ORs, is clearly not the case. Perhaps it is because the Texas Road crossing of Middle Boggy in the Choctaw Nation is so well known and often mentioned in the ORs. Again, there is nothing in the ORs suggesting this vicinity for the battle or Phillips' expedition.
I thought "Civil War Sites in Oklahoma" by Muriel Wright and Leroy Fisher was gospel! I have had this book since about 1972 (bought it when I was 2 years old! LOL). The book is very good but not perfect -- The Battle of Old Boggy Depot occurred on Snake Creek in Haskell County near Stigler, not near Boggy Depot (the men were traveling 'from' Boggy Depot); and the Battle of Backbone Mountain was in Sebastian County, Arkansas near Greenwood, not in LeFlore County OK.
I continue to search for 'eyewitness accounts' that would give more evidence as to the precise location of battle and Phillips route and campsites. All the Official Records, diaries, memoirs, family stories etc can have errors. Period newspapers have the most inaccurate and outlandish stories from gossip and rumor though they also published letters of eyewitnesses and official reports. The Indian Territory was poorly mapped and had not been surveyed (township surveys were done in the 1890s). The challenge is to find enough corraborating evidence to support a location.