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Rating depth structure for largemouth bass.
Shared by DepthScout anglers. Exact spots stay private, always.
905-acre lake in Williamson County, Illinois. The lake tops out around 65 ft. This chart interpolates between a real shoreline and a known maximum depth. It will point you at likely water, but it is not a navigation product. What the data behind the map says about each species, season by season:
Little Grassy Lake maps at 913 acres behind 25.2 miles of shoreline, with 2 islands in the mix. An index of 6 puts the bank firmly in maze territory: point after pocket after cove, every one a casting target. 34% of the surface is littoral (under ~15 ft), per the model — cover, weeds and forage water. End to end it runs roughly 3.5 mi, about 2.3 mi across. It sits in Williamson County. If the bite dies, Devils Kitchen Lake is 3 mi to the east.
Spring bluegill on Little Grassy Lake hold shallow, usually 1 to 6 ft. By summer they slide out to 4 to 15 ft, and by winter most fish are in 10 to 25 ft. The chart's best answer is Shallow bay flat — weed flat, 6 ft, prime for spring. Prime time lands in early morning and the evening. The summer box starts with a small sponge spider (fly) or a micro tube jig.
| 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 | Deep basin (55 ft) | Tiny spoon |
Early season channel catfish use the shallows, holding in 3 to 12 ft. Summer is an 8 to 25 ft game here, winter a 20 to 40 ft one. The chart's best answer is Creek inflow — inflow / creek mouth, 7 ft, prime for spring. Best bite is after dark and the evening.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dusk | Creek inflow (7 ft) | |
| Summer | 8 to 25 ft | night & dusk | Creek inflow (7 ft) | |
| Fall | 10 to 30 ft | dusk | Break off the point (29 ft) | |
| Winter | 20 to 40 ft | midday | Break off the point (29 ft) |
Early season largemouth bass use the shallows, holding in 2 to 10 ft. Summer is an 8 to 20 ft game here, winter a 15 to 35 ft one. The chart's best answer is Shallow bay flat — weed flat, 6 ft, prime for spring. Best bite is early morning and the evening. Tie on a texas-rigged 10" worm or a deep-diving crankbait and you're in the game.
| 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 | Main-lake point (16 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (16 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | Break off the point (29 ft) | Blade bait, Jigging spoon |
Little Grassy Lake carries 16 mapped structure features, topping out (or rather bottoming out) at Deep basin, about 55 ft down.
Season dates, license requirements, and size and bag limits for Illinois waters are set by the Illinois DNR — and special regulations can apply to Little Grassy Lake specifically, so confirm the current rules before you fish.
Check the official Illinois fishing regulations →
Little Grassy Lake is about 65 ft (20 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, largemouth bass on Little Grassy Lake.
Shallow bay flat is the top-rated area: a weed flat in about 6 ft of water that rates prime for bluegill in spring. Open the map above to see every rated spot for each 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 Little Grassy 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.
Devils Kitchen Lake 3 mi · Crab Orchard Lake 8 mi · Cedar Lake 8 mi · Dutchman Lake 15 mi · Lake Murphysboro 17 mi · Kinkaid Lake 22 mi · Rend Lake 35 mi · Lake Girardeau 45 mi, MO · General Watkins Conservation Area 46 mi, MO · Washington County Lake 47 mi · Robert G. Delaney Lake Conservation Area 48 mi, MO · Baldwin Lake 57 mi
See how Little Grassy Lake stacks up: best largemouth bass lakes in Illinois · best bluegill lakes in Illinois · best channel catfish 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.