Downstream south from the community of Divide [1], the Big Hole, with great fishing up to this point, becomes a blue-ribbon trout fishery. Brown trout are both huge and abundant. Mid-June, when the salmon flies hatch, marks a frantic season for fish and fishers alike. To the misfortune of the trout, there are several good fishing-access sites between Divide and Glen.
Links:
[1] http://www.moon.com/destinations/montana/butte-helena-and-southwestern-montana/the-big-hole-river-country/the-lower-big-hole/divide