From the Wine Guide:

Norton: This man-made grape, created by Dr. Daniel Norton of Richmond, Virginia in the 1800s, is the oldest grape native to the US. It is grown primarily in the Midwest and Mid-Atlantic regions and is also known as Cynthiana. It makes wines that are distinctly "grapey" and taste like a grape bought in the grocery store, which as unusual as it may sound, is very rare in wines and not often sought after.