Historic Columbus, Tennessee (defunct town); thoughts about its location

Early in February 1864, Federal troops began to set up camp at some little towns north of Cleveland, Tennessee: Calhoun, Charleston, and Columbus, Tennessee. Calhoun and Charleston were separated by a railroad bridge across the Hiwassee River.

Columbus, a little town in Polk County, Tennessee, is no longer extant. It was once a Cherokee trading town. In winter and early spring of 1864 (from about February), it served as a camp for some Union troops, including the Fourth Indiana Cavalry (Major G.H. Purdy, commanding). Ref.: O.R., Ser. 1, Vol. 32, Pt. 3, 240 (Letter from Maj. G.H. Purdy, HQ at Columbus, Tenn., enclosed in letter from Waterman to Wagner). 

Columbus, Tennessee (Google Map, coordinates from Roadside Thoughts)
Latitude and Longitude: 35.2262 -84.6222

Source for GPS coordinates:

Roadside Thoughts: Columbus, Tennessee

http://roadsidethoughts.com/tn/columbus-xx-polk-summary.htm

But, here is my own calculation of where it would be located on today's Google satellite map, as compared to the 1865 map below it (keeping in mind that the old maps were sometimes pretty vague and could be off). My placement of it is well west of the one designated by coordinates, above, from Roadside Thoughts. Judging by the old map and by the description given on the Polk County Cemeteries page of TNGenWeb, it is about four miles north of Benton. I place it at the intersection of Athens Road and Dentville Road, northwest of the bend in the river. Columbus Road, a throwback to the historic placename, starts in the middle of nowhere on Bowater Road and runs south almost to the Hiwassee River. Then it runs in a curving path, more-or-less parallel to the river, until it intersects Dentville Road. Columbus Road ends there.

Columbus, Tennessee (historic, non-extant town; location estimated by Southern Muse):

Columbus, Tennessee (Google Map est.) 

https://goo.gl/maps/UqnAbKaFmA62

based on the map below, drafted 1863-1864 and published 1865:

Library of Congress, Geography and Map Division: Mountain
Region of NC and Tenn (dtl, Columbus, Tenn. area)

"Polk County, Tennessee Cemeteries" on Tennessee GenWeb website places Columbus Cemetery four miles north of Benton, Tennessee. Presumably the cemetery would be in the town itself.

Columbus Cemetery Description on TNGenWeb site

http://www.tngenweb.org/polk/polkcem.htm

Find A Grave has a cemetery for Columbus, Tennessee, but has no GPS coordinates for it.

http://bit.ly/FindAGrave-ColumbusCemetery-PolkCountyTN

CITATION (1865 MAP)

Nicholson, W. L, A Lindenkohl, H Lindenkohl, Charles G Krebs, and United States Coast Survey. Mountain region of North Carolina and Tennessee. [S.l., U.S. Coast Survey, A. D. Bache, Supt, 1865] Map. Retrieved from the Library of Congress, https://www.loc.gov/item/99447196. (Accessed July 04, 2016.)