Gettysburg Battlefields (Pennsylvania):
July 1-3, 1863: Between 46,000 to 51,000 men died. Much has been reported here including apparitions, soldier units marching, gunfire, voices, and cannonball sounds. Of all outdoor haunted locations, this one has more photographic evidence, both still and video. For many, if you were to go to one outdoor location and want a "guaranteed" experience, the battlefields of Gettysburg provide.
"Suicide Forest" (Aokigahara, Mt. Fuji, Japan):
You might have seen this one on "Destination Truth." This intensely thick forest, that most people get very lost inside of (on the base of Mt. Fuji) is also a popular place for people to go to off themselves. Besides the creepy artifacts one can find there left behind by those who camped before they died, there are reports of full body apparitions and voices, moaning, and crying.
Forest Clearing (Hoia-Baciu, Romania):
Another fantastic episode of "Destination Truth" covered this strange circular clearing in the woods of Romania where one of the crew members was tossed and his arm scratched up. They found no logical reason why there were no trees in this one circle in the forest. Strange lights were seen within the trees and women's voices. The man thrown said it felt like some kind of force swooped down and hit him full blast, sending him sprawling. He had scratches on his arm that was covered by a sleeve. Another crew member got sick to his stomach. These were things reported there before. In fact, it was such a great location, DT is going back there next season--yahoo! Hopefully this time, they won't fly in a plane that loses its roof as they are landing.
Bachelor's Grove Cemetery (Illinois):
This quaint countryside cemetery was actually once a favorite place for families to visit with the pond and the quiet beauty. Much is reported but not supported about colored lights, a phantom car, ghosts. Many tall tales of the history of this site and what happened there were passed down like urban legends and have since been disputed by historians. Whether or not this cemetery is haunted, it's certainly accepted as haunted by the tales that are perpetuated.
"Doll Island" (Mexico):
This location was the home of a man who felt that a girl who drowned in the canal near his land haunted the place. He placed dolls around to appease her and, over the decades, more and more dolls were added until the entire island was decorated with them. This was also a location for "Destination Truth." It was chilling and spine-tingling. I would love to do this to a backyard. It's hard to tell if there is genuine haunting here, as the land is privately owned, but DT's episode had some interesting stuff happening.