Probably fracking rigs. Where I'm from in the Marcellus shale region of Western Pennsylvania, you can see rigs on top of hills for miles when the leaves are dow

Probably fracking rigs. Where I'm from in the Marcellus shale region of Western Pennsylvania, you can see rigs on top of hills for miles when the leaves are down in winter Edit: This map of Bakken Formation rigs correlates to their location in Western ND https://en.wikipedia.org/wiki/Bakken_Formation#/media/File:Bakken_Wells_2008.png https://en.wikipedia.org/wiki/Bakken_Formation#/media/File:B...