If by your first definition that the South is as far as a monument to the Confederate soldier then I would have to say its at least as far west as here as my home town of Richmond, Texas. Please look up the Jay-bird Woodpecker Memorial, and I challenge anyone who thinks the South isnt in Texas to say that to the descendants of the Old Three Hundred here in Texas...or to some of the members of my church.
anyone who thinks Texas ain’t Southern need only cross the border into New Mexico and hear the accents change immediately
West Texas is physically different than the older South, but it was largely settled by Southerners and is Southern in sentiment.