Lake Cumberland is one of the most well known lakes in the Appalachian area of the United States. It's actually a reservoir lake, located in southern Kentucky, west of the Daniel Boone Forest. With a shoreline of over 2k km (about 1.2k mi.), it's one of the ten largest reservoir lakes in the USA by water volume - enough to cover the state of Kentucky with almost 10 cm (about 3.5 inches) of water! Check out this beautiful Appalachian lake from above, compliments of contributor Flintknoop.