Every spot has a NAVIGATE box. Open Google Maps, paste the coordinates exactly as printed (e.g. 42.6432, -112.0052) into the search bar, tap the pin, tap Directions. Where a place-name search also works it's listed — but coordinates always win, and two spots (marked EST) are unsigned roadside pullouts where the pin is approximate: slow down and watch for the brown IDFG access sign.
IDFG owns ~1 mile of river with walk access both directions — one of the only public parcels between Chesterfield and McCammon. ~3,000 catchable rainbows stocked into this corridor in July (Jul 13/15/22) plus wild browns & cutthroat. Flow 71 cfs: low, clear, easy banks. Highest fish-count water on this list.
Purpose-built shore fishery on the west bank below the powerhouse — gravel footpath along the river. Big rainbows, browns, and excellent August smallmouth. Cold releases make it heat-proof on the 98° day. Flow is heavy (10,600 cfs, ~2.25× normal): fish rock seams and slack pockets from shore, no wading. Reservoir hit 3% capacity, so trout may run fewer/smaller this year — smallmouth compensate.
1,000 rainbows stocked at/around the campground in July plus wild cutthroat. Spring-fed creek at 6,500 ft with a walk-along trail — stays cool all day, the perfect midday escape when the Portneuf warms.
1,000 rainbows stocked up the drainage in July + wild cutthroat and rainbows. IDFG calls it “good creek fishing.” Coolest water in the Portneuf system — a solid all-day option and a natural pair with a Chesterfield loop.
Wild-fish water above Lava: browns and cutthroat in spring-fed flows, nobody around. Bait is legal here in August — the no-bait/catch-and-release rule on this stretch only runs Dec 1 to Memorial Day weekend.
Basalt-canyon shoreline with lots of walkable rock. Below Eagle Rock you’re back to the 6-trout limit, and August smallmouth fishing here is genuinely excellent. The move if Duck Puddle is crowded.
Best trout river in the region and rainbow harvest is UNLIMITED — IDFG wants them out (browns limit 2, cutthroat zero). Running 12,100 cfs: big water, edges only, no wading. Bank angler’s play = the lower-river side channels, where displaced fish stack in small water; shop reports have fish “tight against the banks in the first 10 feet of current.” Boat traffic is heavy — fish early.
The canyon below the dam is the one Blackfoot section with water (451 cfs release; the river near town is dewatered to 32 cfs). Walkable BLM banks, gorgeous. Ranked low for bait: it’s dominated by wild Yellowstone cutthroat and every cutt must go back — bait-hooked cutts often swallow the hook. Better fly/lure water; whitefish are fair game.
Portneuf mainstem access with room to walk a long way alone. Same general rules as the lower river.
Wild browns and cutthroat in beaver-dam pocket water on NF land. Technically close to town but fully rural — the quick after-dinner option.
Dawn: Lower Portneuf Access (#1) — drift worms through the holes on the IDFG mile; fresh stockers, limit potential.
~11am: up to Big Springs on Pebble Creek (#3) — cool midday creek fishing over July stockers.
Evening: back to the Portneuf (#1 or #5) until dark.
First light: American Falls tailwater (#2) — coldest water on the hottest day, biggest fish of the trip. 2-trout cap. Done by noon.
Evening (optional): Toponce (#4) or Mink Creek (#10).
Swap: want size over numbers? Make Friday the South Fork side-channel day (#7) — dawn at Lorenzo/Twin Bridges, unlimited rainbows.
| Gauge | Site # | Aug 6 reading | Want |
|---|---|---|---|
| Portneuf @ Topaz (above Lava) | 13073000 | 71 cfs | 50–150 cfs = good |
| Snake below American Falls (Neeley) | 13077000 | 10,600 cfs | fishable from rocks at any release; skip wading |
| Blackfoot canyon (nr Shelley) | 13066000 | 451 cfs | 200–800 = normal band |
| South Fork @ Irwin | 13032500 | 12,100 cfs | edges/side channels only above ~10k |