Major UP river system with multiple branches. Steelhead and brown trout in lower sections; brook trout in the headwaters. Ottawa National Forest surrounds much of the river.
Species present: Brook trout, Brown trout, Steelhead trout. Stream type: freestone.
Based on current water temperature and time of year, the following insects are active or expected on the Ontonagon River.
| Hatch | Latin | Top Patterns | Time of Day |
|---|---|---|---|
| Midge | Chironomidae | Mercury Midge #20, Zebra Midge #20 | midday |
| Blue-Winged Olive (Baetis) | Baetis spp. | Parachute BWO #16, Sparkle Dun BWO #16 | midday |
| BWO (Fall) | Baetis tricaudatus | Parachute BWO #16, Pheasant Tail Nymph #16 | midday |
| Fall Caddis | Neophylax spp. | Orange Elk Hair Caddis #14, LaFontaine Pupa (orange) #14 | afternoon |