Armagnac, located in the Southwest of France (south of Bordeaux) is the lesser-known cousin to Cognac. Armagnac is much older, as a truly identified brandy-producing region, than is Cognac.
The primary flavor difference is derived from the fact that Armagnac (traditionally) is single distilled as opposed to the double distilled technique used in Cognac. Armagnac uses a variety of grapes as opposed to primarily one used in Cognac. Traditionally bottled at natural strength with the vintage date present on the label.