My understanding is that eastern MT is being fracked. It should be on the map. PA too.
Eastern Montana is in the Williston Basin, the same geologic province as Western North Dakota and even part of South Dakota, not to mention parts of Manitoba, Saskatchewan, and Alberta.
For some reason the media have renamed the region "the Bakken" after one of many geological formations there, and one which outcrops nowhere (it is entirely in the subsurface). Now, while that makes as much sense as calling the Appalachians the Beekmantown (or the Knox further south), that doesn't stop the scribblers from doing it.
The Bakken boom really started in Eastern Montana (with horizontal wells not in the shale but the middle member of the Bakken Formation), in what became the Elm Coulee Field in Richland County in 1999. It didn't really take off until roughly 2005/6 in North Dakota, when some very good wells were drilled near Stanley, ND. It spread rapidly from there.
I think it is the top fracking states. Ohio is being fracked quite a bit around Youngstown. I just think these are the top states.