Idaho reservoir guide
Blackfoot Reservoir Fishing
Blackfoot Reservoir is a large southeast Idaho irrigation reservoir with a strong trout focus and an established smallmouth bass fishery. Recent IDFG surveys continue to document cutthroat and rainbow trout, perch and bass, and IDFG stocked roughly 30,000 catchable triploid rainbows in April 2026. The reservoir has unusually strong physical-data support: a USGS multibeam bathymetric survey revised its stage-capacity relation and put design maximum pool at 6,124 feet with 333,500 acre-feet of capacity. Water levels can fluctuate with irrigation demand.
LocationBingham and Caribou Counties, Idaho
Primary targetsSmallmouth Bass, Rainbow Trout, Yellow Perch
Best seasonSpring through fall
Lake size16,887.9 acres (IDFG); about 18,000 acres when full (BLM)
Guide reviewed
Scientific profile
Research snapshot
Elevationabout 6,120 feet operating/full-pool range
Public launches2
Summer cautionHeat
Lake map
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What makes Blackfoot Reservoir distinctive
Blackfoot Reservoir covers roughly 16,888 surface acres, making it one of the larger waters represented in FishyNW.
Blackfoot Reservoir sits at roughly 6,120 feet in elevation, so seasonal access and water temperature can differ sharply from lowland lakes.
Blackfoot Reservoir is documented in Bingham and Caribou Counties County with a dedicated FishyNW fishing and access profile.
Measured & official data
Water Science
Loading available public monitoring and fishery science…
Pass 3 · depth + water column
Seasonal Fish Habitat
Surface · 0 ft
How to read this data
Temperature, dissolved oxygen, clarity, nutrients, chlorophyll-a, pH, and conductivity are observations from public monitoring records and may be historical. Thermocline depth is shown only when FishyNW can derive a strong vertical temperature gradient from a measured profile. It is not treated as a permanent lake characteristic.
Trophic indication uses the Carlson Trophic State Index only when FishyNW can normalize a measured chlorophyll-a, Secchi, or total-phosphorus value. It is a derived ecological indicator, not an agency impairment determination.
Seasonal Fish Habitat is shown only when verified bathymetry overlaps a same-day, same-station temperature and dissolved-oxygen profile. It is a historical screening snapshot, not a live prediction of where fish are located.
For lake trout, FishyNW uses the broader USGS-tested screening combination of water at or below 15°C (59°F) and dissolved oxygen at or above 4 mg/L. For other coldwater species, FishyNW does not invent a preferred-temperature threshold; it shows only the observed thermocline-to-oxygenated-depth refuge when the evidence supports it.
Harmful-algae status is never inferred from missing data. Always check the linked state source for current advisories before contact recreation.
Open matched Water Quality Portal recordsFishery record
Documented fish species
These species come from the lake record. Open a species guide for identification, seasonal behavior, and practical tactics without confusing general species guidance with a lake-specific survey result.
Bass and sunfish
Smallmouth Bass
Focus on rock, points, breaks, and transitions.
View species guide
Trout and salmon
Rainbow Trout
Use bait, small spinners, spoons, or slow trolling depending on access.
View species guide
Perch and pike
Yellow Perch
Use small jigs, bait, or dropper rigs near schools.
View species guide
Trout and salmon
Cutthroat Trout
See seasonal habitat, presentations, identification, and regulation cautions.
View species guide
Whitefish
Mountain Whitefish
See cold-water habitat, seasonal movement, and presentation tips.
View species guide
Fishery intelligence
Official fishery evidence
Agency survey records and measured fishery data, distilled for trip planning.
5
verified signals
Research & surveys
Agency-backed record
Use the evidence
Turn records into a fishing plan
- Compare survey evidence with the seasonal guide.
- Use the map to connect depth, access, and structure.
- Confirm current rules and access before your trip.
Trip conditions
Current conditions
Loading the local forecast. Check access and official notices before leaving.
TodayLoading
WindLoading
GustsLoading
Rain chanceLoading
Four day outlook
Tools
Today's Lure Pick
Open Tools for species-specific lure guidance.
Angler interpretation
How the fishery changes through the seasons
This is the practical layer: use it alongside the documented species, depth, stocking, survey, access, and regulation record above. The current season opens first.
Spring
trout, bass- Start here
- Cooler water, recent stocking, fish moving shallow, and protected shorelines or inlets that warm first.
- Watch for
- Cold fronts, changing water levels, muddy inflow, and early-season ramp conditions.
Summer
bass, panfish- Start here
- Fish early or late, then adjust toward deeper water, shade, vegetation, or comfortable temperature zones.
- Watch for
- Heat, weeds, algae, heat, and heavier boat traffic.
Fall
trout, bass- Start here
- Cooling water, shoreline structure, points, weed edges, and simple presentations that let you cover water.
- Watch for
- Wind on open water, rapidly changing weather, and shorter daylight windows.
Winter
perch, trout- Start here
- Legal open-water or ice access, stable depth zones, and conservative cold-weather trip plans.
- Watch for
- Ice safety where relevant, ramps, road conditions, cold-water exposure, and current rules.
Know before you go
Rules and restrictions
Blackfoot Reservoir: trout limit 6 with no harvest of cutthroat trout. Bass have no size, bag or possession limit under the current special rule. Verify current IDFG regulations before fishing.
Keep exploring
Nearby waters
Twentyfour Mile Creek Reservoir #1
about 14.8 miles away
Twentyfour Mile Creek Reservoir 1 is documented by Idaho Fish and Game with a current mapped water identity,…
Kelly Park Pond about 15.1 miles awayKelly Park Pond is part of the August 2026 Idaho expansion research set. Official Idaho fishery, access, regulation,…
Alexander Reservoir about 16.4 miles awayAlexander Reservoir near Soda Springs is a large, accessible reservoir supporting trout, yellow perch, smallmouth bass and catfish.
Chesterfield Reservoir about 18.9 miles awayChesterfield Reservoir, also known as Portneuf Reservoir, is a heavily managed southeast Idaho trout fishery with developed boating…
Blackfoot River River systemA long southeastern Idaho tributary with very different fisheries above Blackfoot Reservoir and below Blackfoot Dam. Upper reaches…
After the trip
Log what happened on the water
Use CatchSignal for catch reports, trip history, photos, and community activity. Keep your fishing history while controlling how much location detail you share.
Sources & feedback
Verified resources
Official links for this lake
Open the source that matches what you are planning.
Community feedback
See something that needs an update?
Send the correction and, when possible, the source. FishyNW reviews submissions before changing the guide.