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6,830-acre flowage near Mosinee. The lake tops out around 46 ft. What you see is a modeled chart: the shoreline is real, the max depth is published, and the contours between are estimated. Plan with it; don't navigate by it. Below is the species-by-species picture, pulled from the same data the map uses.
Drawn out, this is 6,445 acres of water rimmed by 57.6 miles of bank. That shoreline is heavily fingered (development index 5.1) — bays, points and pockets everywhere, which multiplies the fishable edge. 78% of the surface is littoral (under ~15 ft), per the model — cover, weeds and forage water. The basin spans about 12.1 mi end to end and 2.4 mi across at its widest. The water lies in Marathon County. For a second option, Smoky Hill Flowage, North lies 3 mi southwest.
Spring walleye on Big Eau Pleine Reservoir hold shallow, usually 4 to 15 ft. They move out to 15 to 35 ft in summer and finish the year down in 20 to 40 ft. Put Fenwood Creek inflow first on the milk run — an inflow / creek mouth near 5 ft that grades prime for spring. The feeding windows run the evening and early morning. The summer box starts with a crawler harness on bottom bouncer or a deep crankbait (trolled).
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | Fenwood Creek inflow (5 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Break off the point (21 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | Break off the point (21 ft) | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | Deep basin (39 ft) | Jigging spoon + minnow head, Rattle bait |
In spring, crappie run shallow here, mostly 2 to 8 ft. Summer pushes them deeper, 10 to 25 ft, and winter fish settle into 15 to 35 ft. Old creek channel is the standout, a creek channel at roughly 23 ft, rated prime for summer crappie. Time it for early morning and the evening. You won't need more than a jig trolled/spider-rigged or a small crankbait (trolled) most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (6 ft) | 1/16 oz jig + tube, Curly-tail grub |
| Summer | 10 to 25 ft | dawn & dusk | Old creek channel (23 ft) | Jig trolled/spider-rigged, Small crankbait (trolled) |
| Fall | 8 to 20 ft | dawn | Old creek channel (23 ft) | Jig + minnow combo, Small swimbait (1.5-2") |
| Winter | 15 to 35 ft | midday | Old creek channel (23 ft) | Tungsten jig + soft plastic, Tiny jigging spoon |
Start shallow in spring: bluegill sit in 1 to 6 ft that time of year. Summer pushes them deeper, 4 to 15 ft, and winter fish settle into 10 to 25 ft. The spot to know is Shallow bay flat, a weed flat in about 6 ft of water that rates prime for bluegill in spring. Warm-month bites cluster around early morning and the evening. Throw a small sponge spider (fly) or a micro tube jig until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | Shallow bay flat (6 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow bay flat (6 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Shallow bay flat (6 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 10 to 25 ft | midday | Break off the point (21 ft) | Tungsten ice jig + plastic, Tiny spoon |
Early season yellow perch use the shallows, holding in 3 to 12 ft. Expect a summer slide to 10 to 30 ft, then a winter hold in 15 to 35 ft. Put Shallow bay flat first on the milk run — a weed flat near 6 ft that grades prime for spring. In summer the feeding windows fall in early morning. Tie on a drop-shot micro plastics or a small spoon tipped with worm and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (6 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Break off the point (21 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Break off the point (21 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Deep basin (39 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Spring puts largemouth bass in skinny water — 2 to 10 ft is the zone. As the season builds they drop to 8 to 20 ft, wintering in 15 to 35 ft. Spring largemouth bass concentrate at Shallow bay flat, a prime-rated weed flat around 6 ft. Warm-month bites cluster around early morning and the evening. A texas-rigged 10" worm or a deep-diving crankbait covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (6 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Break off the point (21 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (12 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | Break off the point (21 ft) | Blade bait, Jigging spoon |
Spring puts channel catfish in skinny water — 3 to 12 ft is the zone. As the season builds they drop to 8 to 25 ft, wintering in 20 to 40 ft. Spring channel catfish concentrate at Fenwood Creek inflow, a prime-rated inflow / creek mouth around 5 ft. Warm-month bites cluster around after dark and the evening.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dusk | Fenwood Creek inflow (5 ft) | |
| Summer | 8 to 25 ft | night & dusk | Old creek channel (23 ft) | |
| Fall | 10 to 30 ft | dusk | Old creek channel (23 ft) | |
| Winter | 20 to 40 ft | midday | Deep basin (39 ft) |
Big Eau Pleine Reservoir carries 14 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 39 ft down.
Access data: Wisconsin DNR — Boat Access Sites. Confirm conditions and fees locally before you launch.
Season dates, license requirements, and size and bag limits for Wisconsin waters are set by the Wisconsin DNR — and special regulations can apply to Big Eau Pleine Reservoir specifically, so confirm the current rules before you fish.
Check the official Wisconsin fishing regulations →
Big Eau Pleine Reservoir is about 46 ft (14 m) deep at its deepest point. The contours here are modeled from the water's real shape and maximum depth, so treat them as a rough guide.
Anglers target walleye, crappie, bluegill, yellow perch, largemouth bass, channel catfish on Big Eau Pleine Reservoir.
Fenwood Creek inflow is the top-rated area: an inflow / creek mouth in about 5 ft of water that rates prime for walleye in spring. Scroll up to the map for the complete spot list by species and season.
For walleye, the summer bite is best in the evening and early morning. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Fishing on Big Eau Pleine Reservoir is regulated by the Wisconsin DNR. Check the official Wisconsin regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Smoky Hill Flowage, North 3 mi · Berkhahn Flowage (Townline) 4 mi · North Rice Lake 4 mi · Honey Island Flowage, West 4 mi · Honey Island Flowage 4 mi · Townline Reservoir* 5 mi · Mosinee Flowage 9 mi · Lake Du Bay 9 mi · Anderson Lake 14 mi · Lake Wausau 17 mi · Eau Claire Flowage (Schofield) 17 mi · Wisconsin R Fl C3-Stevens Pt 19 mi
See how Big Eau Pleine Reservoir stacks up: best largemouth bass lakes in Wisconsin · best walleye lakes in Wisconsin · best crappie lakes in Wisconsin · best bluegill lakes in Wisconsin
More water nearby: Marathon County fishing maps (27 charts). Browse all Wisconsin fishing maps or see every water on DepthScout. How we build these maps. Fish here with a sonar unit that logs? Send us your depth data and we'll improve this chart, credited to you. For fishing guidance only, never navigation.