In Tennessee, generally speaking the single digit highways are some of the most important routes across the state. The routes are so important that in many cases these important TN routes also are US Routes. If a state route is going to follow a US route for an extended distance, there's no point in putting up both signs ans the federal sign prevails. TN6 is this was, as it's entire course through the state is concurrent with a US Highway. I was under the impression that I'd never find a TN6 highway sign in the entire state. I happened to stumble across this one. I suspect at one time the TN6 designation made it all across the state, then later as a cost-cutting matter, all of the TN6 signs were taken down so that new numbers could be affixed to the sign and save the cost of making a brand new sign. I don't know how long ago that happened, but they missed one. The sign even looks like it's decades old with some of the black paint fading and the 6 is cracking. Finding this made me happier than it ought to have. When it begins on the south side of the state at the Alabama state line, TN6 is concurrent with US 43 until that route ends in Columbia. From Columbia, TN6 follows US 31 until it splits in Nashville. From Nashville, where it then follows US 31E to the Kentucky state line. On the north side of Nashville where US31E is the Ellington Parkway, there are mile marker signs that have a TN6 logo. This particular sign was spotted near an intersection with US 43 just north of Loretto along Busby Rd. If you're as much of a roadgeek as I am, I have a similar writeup on TN 1 and TN 2.