Rockbridge County is a county in the Shenandoah Valley on the western edge of the Commonwealth of Virginia. As of the 2020 census, the population was 22,650. Its county seat is the city of Lexington. Rockbridge County completely surrounds the independent cities of Buena Vista and Lexington. The Bureau of Economic Analysis combines the independ…Rockbridge County is a county in the Shenandoah Valley on the western edge of the Commonwealth of Virginia. As of the 2020 census, the population was 22,650. Its county seat is the city of Lexington. Rockbridge County completely surrounds the independent cities of Buena Vista and Lexington. The Bureau of Economic Analysis combines the independent cities of Buena Vista and Lexington with Rockbridge County for statistical purposes.