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523-acre lake in Marion County, Illinois. The lake tops out around 28 ft. The contours come from a model of the real basin shape and its known max depth. Read them as probabilities, not soundings, and keep them out of navigation decisions. Here is how the season plays out for each species, straight from the data behind the map.
Drawn out, this is 503 acres of water rimmed by 15.5 miles of bank, broken up by an island. The 4.9 development index tells the story — a convoluted bank whose fishable edge far outruns the acreage. About 92% of the surface sits shallower than 15 ft on the modeled chart — that's the weed-and-bait zone. Figure 2.8 mi of water from one end to the other, 1.3 mi at the beam. The water lies in Marion County. The nearest mapped water is Sam Dale Lake, 16 mi to the southeast.
In spring, bluegill run shallow here, mostly 1 to 6 ft. Summer pushes them deeper, 4 to 15 ft, and winter fish settle into 10 to 25 ft. Shallow bay flat is the standout, a weed flat at roughly 3 ft, rated prime for spring bluegill. Time it for early morning and the evening. You won't need more than a small sponge spider (fly) or a micro tube jig most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | Shallow bay flat (3 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow bay flat (3 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Shallow bay flat (3 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 10 to 25 ft | midday | Deep basin (24 ft) | Tungsten ice jig + plastic, Tiny spoon |
The spring pattern is a shallow one: channel catfish in 3 to 12 ft. As the season builds they drop to 8 to 25 ft, wintering in 8 to 28 ft. Top water on the chart: Deep basin, a deep basin in the 24 ft range, prime in winter. Time it for after dark and the evening.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dusk | Shallow bay flat (3 ft) | |
| Summer | 8 to 25 ft | night & dusk | Deep basin (24 ft) | |
| Fall | 8 to 28 ft | dusk | Deep basin (24 ft) | |
| Winter | 8 to 28 ft | midday | Deep basin (24 ft) |
Spring puts common carp in skinny water — 2 to 10 ft is the zone. Warm water sends them out to 3 to 15 ft; cold water stacks them in 8 to 28 ft. Shallow bay flat is the standout, a weed flat at roughly 3 ft, rated prime for spring common carp. Plan around early morning and the evening in the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | midday & dawn | Shallow bay flat (3 ft) | |
| Summer | 3 to 15 ft | dawn & dusk | Shallow bay flat (3 ft) | |
| Fall | 5 to 18 ft | midday | Shallow bay flat (3 ft) | |
| Winter | 8 to 28 ft | midday | Deep basin (24 ft) |
Start shallow in spring: crappie sit in 2 to 8 ft that time of year. Summer pushes them deeper, 10 to 25 ft, and winter fish settle into 8 to 28 ft. The spot to know is Deep basin, a deep basin in about 24 ft of water that rates prime for crappie in winter. Warm-month bites cluster around early morning and the evening. Throw a jig trolled/spider-rigged or a small crankbait (trolled) until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (3 ft) | 1/16 oz jig + tube, Curly-tail grub |
| Summer | 10 to 25 ft | dawn & dusk | Deep basin (24 ft) | Jig trolled/spider-rigged, Small crankbait (trolled) |
| Fall | 8 to 20 ft | dawn | open water | Jig + minnow combo, Small swimbait (1.5-2") |
| Winter | 8 to 28 ft | midday | Deep basin (24 ft) | Tungsten jig + soft plastic, Tiny jigging spoon |
The spring pattern is a shallow one: largemouth bass in 2 to 10 ft. As the season builds they drop to 8 to 20 ft, wintering in 8 to 28 ft. Top water on the chart: Shallow bay flat, a weed flat in the 3 ft range, prime in spring. Time it for early morning and the evening. Summer baits: a texas-rigged 10" worm or a deep-diving crankbait gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (3 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Main-lake point (8 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (8 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 8 to 28 ft | midday | Deep basin (24 ft) | Blade bait, Jigging spoon |
Early season saugeye use the shallows, holding in 3 to 12 ft. Expect a summer slide to 8 to 22 ft, then a winter hold in 8 to 28 ft. Put Deep basin first on the milk run — a deep basin near 24 ft that grades prime for winter. In summer the feeding windows fall in the evening and early morning. Tie on a crawler harness (shallow) or a jig + crawler and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dusk & dawn | Main-lake point (8 ft) | 1/8 oz jig + twister tail, Blade bait |
| Summer | 8 to 22 ft | dusk & dawn | Main-lake point (8 ft) | Crawler harness (shallow), Jig + crawler |
| Fall | 8 to 28 ft | dusk & dawn | Main-lake point (8 ft) | Blade bait, Jigging rap |
| Winter | 8 to 28 ft | dusk & dawn | Deep basin (24 ft) | Jigging spoon + minnow head, Blade bait |
Forbes Lake also holds striped bass (8 to 28 ft in summer), white bass & hybrids (8 to 28 ft in summer). Pick any of them on the map above for rated spots and bait picks.
5 pieces of structure are mapped here — Deep basin, around 24 ft, is the deepest of them.
Season dates, license requirements, and size and bag limits for Illinois waters are set by the Illinois DNR — and special regulations can apply to Forbes Lake specifically, so confirm the current rules before you fish.
Check the official Illinois fishing regulations →
Forbes Lake is about 28 ft (9 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 bluegill, channel catfish, common carp, crappie, largemouth bass, saugeye, striped bass, white bass & hybrids on Forbes Lake.
Shallow bay flat is the top-rated area: a weed flat in about 3 ft of water that rates prime for bluegill in spring. The map above holds the full rated-spot list for every species and season.
For bluegill, the summer bite is best in early morning and the evening. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Fishing on Forbes Lake is regulated by the Illinois DNR. Check the official Illinois regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Sam Dale Lake 16 mi · Lake Centralia 17 mi · Lake Altamont 22 mi · Centralia Reservoir 22 mi · Carlyle Lake 28 mi · Sara Lake 29 mi · Newton Lake 29 mi · East Fork Lake 38 mi · Sam Parr Lake 40 mi · Rend Lake 44 mi · Washington County Lake 44 mi · Lake Mattoon 46 mi
See how Forbes Lake stacks up: best largemouth bass lakes in Illinois · best saugeye lakes in Illinois · best crappie lakes in Illinois · best bluegill lakes in Illinois
Browse all Illinois 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.