Yellowstone National Park, October 12th, 2024
Other than continuing Firehole River BWO and White Miller activity, it essentially “Brown Trout Season” in the park. The Lewis River System offers perhaps the biggest number of migrating browns (mostly of trophy size) in the area. The densest concentration is in the channel between Lewis and Shoshone Lakes where fish from both lakes concentrate. Getting there early in the day to present streamer and large nymph patterns before other wading and bankside anglers disturb the fish is the best strategy. Another location where good numbers of browns concentrate is in the river just below Lewis Lake. Rather than disturbing fish in the act of spawning there, fish the outlet bay in order to intercept migrating browns.
The Madison River drainage features a great run of browns and accompanying rainbows from Hebgen Lake, but the number of fly fishers can equal the number of fish to the point that social problems can arise. Other brown trout runs worth a visit are in the Gardner and Snake Rivers, but these peak a bit later in the season than the Lewis and Madison runs.
Flies to try: