In response to
Edelweiss, the line has been moving steadily South since the
Civil War. Although
Maryland towns (and even some in
Pennsylvania) are built along the same lines as your average
Southern town, Maryland's bond to the South was forever shattered by its refusal to
secede. While
Abraham Lincoln declared
martial law in MD in order to keep the
aristocrats in the state
government from seceding, most of the state had no interest in joining the
Confederate States of America.
Next to fall was Washington, DC. John F. Kennedy famously described Washington as having "Northern charm and Southern efficiency," but DC's last vestiges of Southernness were gone by the 1960s. Now, Northern Virginia is no longer part of the South. One joke outside NoVA is that it's really a separate state; Virginia, and hence The South, begins at Fredericksburg, which is backed up by the placement of the first Virginia Welcome Center on Interstate 95. So the line is currently between Richmond and Washington.
The scary part for this Richmonder, though, is that I can see the line crossing Richmond sometime in the next 20-30 years. I already know several people that commute to Washington or NoVA from Richmond, and the trend will only increase as commuter rail (Virginia Railway Express) extends service to Richmond as planned. My state senator, John B. Watkins, said it -- Richmond is becoming a bedroom city to Washington whether we like it or not. The faster we accept that fact, the better Richmond will be able to plan for and adapt to that role.