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2,187-acre lake near Codington County. The lake tops out around 9 ft. Bathymetry on this water is estimated from its real outline and maximum depth. Use it to shortlist water, then verify with your electronics — and never navigate by it. Every species below gets its seasonal read from the same numbers driving the chart.
Grass Lake maps at 2,226 acres behind 9.7 miles of shoreline. A middling shoreline index (1.5) gives it some bays to work without being a maze. All of it is shallow-zone water — under ~15 ft across the entire basin, so the food chain has the run of the place. End to end it runs roughly 2.6 mi, about 2.2 mi across. Codington County claims this one. Dry Lake sits 3 mi southeast — the closest neighbouring chart.
In spring, yellow perch run shallow here, mostly 2 to 9 ft. Summer keeps them at 3 to 9 ft, and they winter in 3 to 9 ft. Shallow bay flat is the standout, a weed flat at roughly 3 ft, rated prime for spring yellow perch. Time it for early morning. You won't need more than a drop-shot micro plastics or a small spoon tipped with worm most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 9 ft | midday & dawn | Shallow bay flat (3 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 3 to 9 ft | dawn | Deep basin (8 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 3 to 9 ft | midday | Deep basin (8 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 3 to 9 ft | midday & dawn | Deep basin (8 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Early season crappie use the shallows, holding in 2 to 8 ft. Expect a summer slide to 3 to 9 ft, then a winter hold in 3 to 9 ft. Put Deep basin first on the milk run — a deep basin near 8 ft that grades prime for winter. In summer the feeding windows fall in early morning and the evening. Tie on a jig trolled/spider-rigged or a small crankbait (trolled) and you're in the game.
| 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 | 3 to 9 ft | dawn & dusk | Shallow bay flat (3 ft) | Jig trolled/spider-rigged, Small crankbait (trolled) |
| Fall | 3 to 9 ft | dawn | Shallow bay flat (3 ft) | Jig + minnow combo, Small swimbait (1.5-2") |
| Winter | 3 to 9 ft | midday | Deep basin (8 ft) | Tungsten jig + soft plastic, Tiny jigging spoon |
Early season bluegill use the shallows, holding in 1 to 6 ft. Summer is a 2 to 9 ft game here, winter a 3 to 9 ft one. The chart's best answer is Shallow bay flat — weed flat, 3 ft, prime for spring. Best bite is early morning and the evening. Tie on a small sponge spider (fly) or a micro tube jig and you're in the game.
| 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 | 2 to 9 ft | dawn & dusk | Shallow bay flat (3 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 3 to 9 ft | midday | Shallow bay flat (3 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 3 to 9 ft | midday | Deep basin (8 ft) | Tungsten ice jig + plastic, Tiny spoon |
Early season northern pike use the shallows, holding in 2 to 8 ft. Expect a summer slide to 3 to 9 ft, then a winter hold in 3 to 9 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 and the evening. Tie on a bucktail or a weedless spoon over cabbage and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (3 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 3 to 9 ft | dawn & dusk | Shallow bay flat (3 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 3 to 9 ft | midday & dawn | Shallow bay flat (3 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 3 to 9 ft | midday | Shallow bay flat (3 ft) | Tip-ups, Large jigging spoon |
The spring pattern is a shallow one: walleye in 2 to 9 ft. The depth story barely changes: 3 to 9 ft through summer, 3 to 9 ft in winter. Top water on the chart: Break off the point, a drop-off in the 4 ft range, prime in fall. Time it for the evening and early morning. Summer baits: a crawler harness on bottom bouncer or a deep crankbait (trolled) gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 9 ft | dusk & dawn | Main-lake point (8 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 3 to 9 ft | dusk & dawn | Break off the point (4 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 3 to 9 ft | dusk & night | Break off the point (4 ft) | Jigging rap, Jig + big minnow |
| Winter | 3 to 9 ft | dusk & dawn | Deep basin (8 ft) | Jigging spoon + minnow head, Rattle bait |
Spring largemouth bass on Grass Lake hold shallow, usually 2 to 9 ft. Depth-wise the year is flat: 3 to 9 ft in summer, 3 to 9 ft once it turns cold. The chart's best answer is Shallow bay flat — weed flat, 3 ft, prime for spring. Prime time lands in early morning and the evening. The summer box starts with a texas-rigged 10" worm or a deep-diving crankbait.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 9 ft | dawn & dusk | Shallow bay flat (3 ft) | Spinnerbait, Chatterbait |
| Summer | 3 to 9 ft | dawn & dusk | Shallow bay flat (3 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 2 to 9 ft | midday & dawn | Main-lake point (8 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 3 to 9 ft | midday | Break off the point (4 ft) | Blade bait, Jigging spoon |
Grass Lake also holds brown bullhead (2 to 9 ft in summer), white bass (3 to 9 ft in summer). Pick any of them on the map above for rated spots and bait picks.
Structure-wise the chart holds 6 features, led in depth by Main-lake point at roughly 8 ft.
Access data: South Dakota Game, Fish & Parks — Boat Ramps. Confirm conditions and fees locally before you launch.
Season dates, license requirements, and size and bag limits for South Dakota waters are set by the South Dakota Game, Fish and Parks — and special regulations can apply to Grass Lake specifically, so confirm the current rules before you fish.
Check the official South Dakota fishing regulations →
Grass Lake is about 9 ft (3 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 yellow perch, crappie, bluegill, northern pike, walleye, largemouth bass, brown bullhead, white bass on Grass Lake. This isn't a survey of the water — none is published for it — but an informed estimate from the species common to the region, narrowed by this water's depth, size and each species' range.
Shallow bay flat is the top-rated area: a weed flat in about 3 ft of water that rates prime for yellow perch in spring. The map above holds the full rated-spot list for every species and season.
For yellow perch, the summer bite is best in 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 Grass Lake is regulated by the South Dakota Game, Fish and Parks. Check the official South Dakota regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Dry Lake 3 mi · Heggs Lake 8 mi · Long Lake 10 mi · Swan Lake 10 mi · Kampeska Lake 13 mi · Bitter Lake 14 mi · Horseshoe Lake 15 mi · Goose Lake 17 mi · Pelican Lake 17 mi · Reid Lake 18 mi · Blue Dog Lake 20 mi · Summit Lake 23 mi
See how Grass Lake stacks up: best largemouth bass lakes in South Dakota · best walleye lakes in South Dakota · best white bass lakes in South Dakota · best northern pike lakes in South Dakota
More water nearby: Codington County fishing maps (6 charts). Browse all South Dakota 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.