In northwestern Lycoming County, the Slate Run is well-known as one of the states most scenic rivers. There are plenty of brook trout and brown trout just waiting for you. This 7 mile river runs through rugged terrain in a narrow flood plain at the bottom of a 1,000 foot deep gorge.
Head to the upper 3 mile section for early season brook trout, which is accessed by Francis Road. Try your luck at the Morris Run or Red Run confluences just below the Morris Run Road Bridge. Or venture downstream for the brown trout, which is accessed by several secondary roads off of SR414. Note: the access roads are above the gorge, so you can expect a steep hike down.
There are a variety of hatches starting in March and running through early September. Since the gorge and waters are cool, the hatches can be pretty large.
Overall, Slate Run is the 33rd most popular fly fishing river of all 49 fly fishing spots in Pennsylvania.