The term "back country" as it applies to British America, would refer to the interior portions of the colonies, from Pennsylvainia down to the Carolinas. Of the four waves of English emmigration to British America, those who settled in the back country came last, and tended to be from the north border country of Britian, Scotland, and northern Ireland. They gravitated toward and in many cases were encouraged to settle the back country or frontier portions of the colonies.
I believe you'll find that Jefferson, Washington, Madison, Patrick Henry, Mr Lee, and George Mason were Southerners and all were important contributors to the founding concepts.
I think it would be more accurate to say they were all Virginians, and with the possible exception of Patrick Henry were products of the aristocratic tidewater culture.
I also acknowledge the contributions of (especially) Benjamin Franklin, as well as the Adams', Hancock, and others.
And many others, as we both well know.
Why do Northerners feel it is necessary to denigrate the South? Or is it that you can't accept that Southerners were simply tired of getting screwed by the very government they had helped found?
From your response I take you weren't thinking about the tidewater aristocracy when you used the term, but that is the cultural background of virtually all of the southern founders. When you claim that a particular culture by and large wrote the Constitution, Bill of Rights, and the Declaration of Independence, you'd better be prepared to explain (and defend) what culture you're talking about.
Most southerners on these threads tend to disavow a connection to the southern tidewater aristocracy, preferring to embrace the back country (or upcountry) yeomen as their prototype ancestor. Which is fine except that this group was not the culture that our southern founding fathers sprang from. This group was not much interested in participating in the noble experiment of democracy, and they were not represented well amongst the men who came together in New York and Philidelphia to create this great nation.