Came up here in a whim one night and got lucky! No one else camped up there so it was peacful. You're right by the water with. Great mountain view, couldn't ask for more.
There were just a few cars driving back down the mountain in the evening. But no one bothered.
There's a nice hand full of spots you could pull up in a car, maybe two spots your could fit a small trailer in. About four or five fire rings in the immediate area. I wouldn't be surprised in there were more spots in the area or the other side of the reservoir.
Pretty easy to get to from Helena. Just take Rimini road all the way up, past the town, past private property. At some point I took a right onto Goulds.
Not the best roads but I got up there fine with my 2015 Outback just fine.