There’s fishing access to the Missouri River and its tributaries at Missouri Headwaters State Park [1].
The Drouillard Fishing-Access Site offers entry to the Jefferson River on Highway 10 two miles west of Three Forks [2]. The Sappington Bridge crosses the Jefferson on Highway 287 at Highway 10, and the Williams Bridge is just to the east. The Jefferson is deeper and slower than the riffly Madison, but fishing very early or late in the day will often yield brown trout as well as a host of less prestigious whitefish, carp, chubs, and suckers.
Cobblestone, Grey Cliff, and Black’s Ford fishing-access sites are on the lower Madison River between Highway 84 and the Missouri headwaters. To reach this stretch of the Madison, head south on Highway 286 (off I-90 east of Three Forks) or east from Norris on Highway 84, then north on Highway 286.
Camping is permitted at these undeveloped riverside spots, but care should be taken not to stray onto the surrounding private land without permission.
The relatively warm lower Madison, while popular, does not share the incredible reputation of the river’s cooler upper reaches.
There are several pullouts on Highway 84 near the bridge nine miles east of Norris, and the more ambitious angler can head up the trail into Beartrap Canyon [3]
Links:
[1] http://www.moon.com/destinations/montana/the-missouri-headwaters-and-south-central-montana/three-forks-and-the-madison-river-/missouri-headw
[2] http://www.moon.com/destinations/montana/the-missouri-headwaters-and-south-central-montana/three-forks-and-the-madison-river/three-forks
[3] http://www.moon.com/destinations/montana/the-missouri-headwaters-and-south-central-montana/three-forks-and-the-madison-river-/other-recreati