How was the “backcountry” underrepresented, eventually leading to Bacon's Rebellion?

How was the “backcountry” underrepresented, eventually leading to Bacon's Rebellion?

"Backcountry" generally means the rural parts (of Virginia, where this all happened) or the lesser-known parts. They were newer settlement areas, and generally had a far larger population than the older "tidewater" region. How did this mean they were underrepresented / not represented in the House of Burgesses?

Was it because the newer regions were not yet established as actual counties, and thus not able to serve in politics?