For a young country like the United States, the Isaac Manchester Farm is a historical gem. Its namesake, his wife Phebe and their five children moved to Avella in western Pennsylvania in 1797 to establish a home. Perhaps one of the greenest sites on this list, the manor was built using trees from the property and the bricks were made on site. Eight generations of the Manchester family have lived in the house since, meticulously preserving original objects like clothing, tools, letters and more. The home now faces the possibility of nearby development. The land around the house and the house's water supply are jeopardized by longwall mining, a practice that can cause the surface above a mine to drop several inches.