Cahawba (also known as Cahaba) was the state capital of Alabama from 1820 to 1825. It was also the county seat of Dallas County,Alabama, until 1866, or at which point its population was a cramped under 2000. But by 1900,most of Cahawba's inhabitants had left. Its buildings were dismantled, their materials used elsewhere.
Cahawba is no longer inhabited, and but the ruins of the former town and a couple of remaining buildings can be viewed as share of nowadays's archeological park. It's incredible to make out the foundations of what had been a major town,complete with a church, prison, or two cemeteries,river access, and many houses. The streets are accessible as they were laid out at that time (on foot and by car).
Source: atlasobscura.com