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45.7-acre reservoir near Carthage. The lake tops out around 18 ft. The depth chart is built from real state fisheries GPS surveys, so the humps, channels and drop-offs you see are measured, not guessed. The season-by-season read for each species follows, from the map's own numbers.
On the chart, Carthage Reservoir draws 44 acres inside 2.5 miles of shoreline. A development index of 2.7 means a maze of bays and points: far more casting targets than a round bowl of the same size. Roughly 87% of the water is 15 ft or less, the band where the food chain lives. The basin spans about 0.7 mi end to end and 0.4 mi across at its widest. The water lies in Hancock County. For a second option, Mississippi River Pool 19 (Keokuk) lies 12 mi northwest.
Spring puts largemouth bass in skinny water — 2 to 10 ft is the zone. As the season builds they drop to 5 to 18 ft, wintering in 5 to 18 ft. Spring largemouth bass concentrate at Shallow bay flat, a prime-rated weed flat around 3 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 (3 ft) | Spinnerbait, Chatterbait |
| Summer | 5 to 18 ft | dawn & dusk | Break off the point (13 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 | 5 to 18 ft | midday | Break off the point (13 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 5 to 18 ft, wintering in 5 to 18 ft. Winter channel catfish concentrate at Deep basin, a prime-rated deep basin around 18 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 | Shallow bay flat (3 ft) | |
| Summer | 5 to 18 ft | night & dusk | Deep basin (18 ft) | |
| Fall | 5 to 18 ft | dusk | Deep basin (18 ft) | |
| Winter | 5 to 18 ft | midday | Deep basin (18 ft) |
In spring, crappie run shallow here, mostly 2 to 8 ft. Summer pushes them deeper, 5 to 18 ft, and winter fish settle into 5 to 18 ft. Deep basin is the standout, a deep basin at roughly 18 ft, rated prime for winter 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 (3 ft) | 1/16 oz jig + tube, Curly-tail grub |
| Summer | 5 to 18 ft | dawn & dusk | Break off the point (13 ft) | Jig trolled/spider-rigged, Small crankbait (trolled) |
| Fall | 5 to 18 ft | dawn | Break off the point (13 ft) | Jig + minnow combo, Small swimbait (1.5-2") |
| Winter | 5 to 18 ft | midday | Deep basin (18 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 5 to 18 ft. The spot to know is Shallow bay flat, a weed flat in about 3 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 (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 | Break off the point (13 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 5 to 18 ft | midday | Deep basin (18 ft) | Tungsten ice jig + plastic, Tiny spoon |
Start shallow in spring: muskellunge sit in 3 to 12 ft that time of year. Summer pushes them deeper, 5 to 18 ft, and winter fish settle into 5 to 18 ft. The spot to know is Break off the point, a drop-off in about 13 ft of water that rates prime for muskellunge in fall. Warm-month bites cluster around the evening and early morning. Throw a double-10 bucktail or a topwater (walk-the-dog / creeper) until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dusk | Shallow bay flat (3 ft) | Smaller bucktail (#8 blades), 6" glide bait |
| Summer | 5 to 18 ft | dusk & dawn | Main-lake point (8 ft) | Double-10 bucktail, Topwater (walk-the-dog / creeper) |
| Fall | 5 to 18 ft | midday & dusk | Break off the point (13 ft) | Big rubber (Bull Dawg style), 10"+ glide bait |
| Winter | 5 to 18 ft | midday | Deep basin (18 ft) | Large rubber, crawled slow |
Early season yellow perch use the shallows, holding in 3 to 12 ft. Expect a summer slide to 5 to 18 ft, then a winter hold in 5 to 18 ft. Put Shallow bay flat first on the milk run — a weed flat near 3 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 (3 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 5 to 18 ft | dawn | Deep basin (18 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 5 to 18 ft | midday | Deep basin (18 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 5 to 18 ft | midday & dawn | Deep basin (18 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Carthage Reservoir also holds saugeye (5 to 18 ft in summer). Pick any of them on the map above for rated spots and bait picks.
6 pieces of structure are mapped here — Deep basin, around 18 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 Carthage Reservoir specifically, so confirm the current rules before you fish.
Check the official Illinois fishing regulations →
Carthage Reservoir is about 18 ft (5 m) deep at its deepest point. The depth chart here comes from real state fisheries GPS surveys, so the contours reflect measured depths.
Anglers target largemouth bass, channel catfish, crappie, bluegill, muskellunge, yellow perch, saugeye on Carthage Reservoir.
Shallow bay flat is the top-rated area: a weed flat in about 3 ft of water that rates prime for largemouth bass in spring. The interactive chart above rates every spot for each species and season.
For largemouth bass, 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 Carthage Reservoir 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.
Mississippi River Pool 19 (Keokuk) 12 mi, IA/IL · La Harpe Reservoir 15 mi · Pollmiller Park Lake 25 mi, IA · Lake Geode 30 mi, IA · Indian Lake 34 mi, IA · Big Hollow Lake 36 mi, IA · Vermont Lake 37 mi · Siloam Springs Lake 39 mi · Schuy-Rush Lake 40 mi · Lacey Keosauqua State Park Lake 47 mi, IA · Lake Sugema 48 mi, IA · Lake Miss (Tug Fork West) 50 mi, IA
See how Carthage Reservoir 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. Bathymetry credit: state fisheries survey programs. 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.