Montana Trout Fishing interactive map
The whole state of Montana is filled with trout fishing opportunities. I have just given a few general areas below for you to consider.
Here is a link to USGS up to date water level data for the state of Montana
The Missouri river has plenty of access. Its worth a look if you are itching to hook large fish.
This is another of many different options for fishing the southwest corner of Montana.
This is a popular area for fishing the Madison river. The town is pretty fun at night too. It is just a small town pretty much dedicated to fly fishing. The entire economy in the area relies on fishing it seems like.
There are more than a couple trout in the Bighorn river. There are a lot of access points and its easy to float.
This is a smaller river know to house large fish. There are many access sites in the area of the marker on the map.
The Madison river outside of Yellowstone is known to house large brown trout. There are many miles of this river with almost all of it easily accessible.