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Fishing Green Castle Lake: what the data says
26-acre lake near Marshall County. The lake tops out around 23 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. Here is how the season plays out for each species, straight from the data behind the map.
Crappie fishing at Green Castle Lake
Spring crappie on Green Castle Lake hold shallow, usually 2 to 8 ft. They move out to 7 to 23 ft in summer and finish the year down in 7 to 23 ft. The spot to know is Deep basin, a deep basin in about 23 ft of water that rates prime for crappie in winter. Plan around early morning and the evening in the warm months. Summer baits: a jig trolled/spider-rigged or a small crankbait (trolled) gets it done.
| Season | Depth | Best window | Go-to baits |
|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | 1/16 oz jig + tube, Curly-tail grub |
| Summer | 7 to 23 ft | dawn & dusk | Jig trolled/spider-rigged, Small crankbait (trolled) |
| Fall | 8 to 20 ft | dawn | Jig + minnow combo, Small swimbait (1.5-2") |
| Winter | 7 to 23 ft | midday | Tungsten jig + soft plastic, Tiny jigging spoon |
Bluegill fishing at Green Castle Lake
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 7 to 23 ft. If you only fish one area, make it Shallow bay flat: a weed flat around 2 ft that scores prime in spring. Plan around early morning and the evening in the warm months. Tie on a small sponge spider (fly) or a micro tube jig and you're in the game.
| Season | Depth | Best window | Go-to baits |
|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Micro jig + waxworm, Small spoon tipped |
| Winter | 7 to 23 ft | midday | Tungsten ice jig + plastic, Tiny spoon |
Largemouth Bass fishing at Green Castle Lake
Spring largemouth bass on Green Castle Lake hold shallow, usually 2 to 10 ft. Summer pushes them deeper, 8 to 20 ft, and winter fish settle into 7 to 23 ft. The spot to know is Shallow bay flat, a weed flat in about 2 ft of water that rates prime for largemouth bass in spring. Best bite is early morning and the evening. A texas-rigged 10" worm or a deep-diving crankbait covers the summer program.
| Season | Depth | Best window | Go-to baits |
|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Squarebill crankbait (shad), Spinnerbait |
| Winter | 7 to 23 ft | midday | Blade bait, Jigging spoon |
Channel Catfish fishing at Green Castle Lake
Start shallow in spring: channel catfish sit in 3 to 12 ft that time of year. Summer pushes them deeper, 7 to 23 ft, and winter fish settle into 7 to 23 ft. If you only fish one area, make it Deep basin: a deep basin around 23 ft that scores prime in winter. Best bite is after dark and the evening.
| Season | Depth | Best window | Go-to baits |
|---|---|---|---|
| Spring | 3 to 12 ft | dusk | |
| Summer | 7 to 23 ft | night & dusk | |
| Fall | 7 to 23 ft | dusk | |
| Winter | 7 to 23 ft | midday |
Yellow Perch fishing at Green Castle Lake
Start shallow in spring: yellow perch sit in 3 to 12 ft that time of year. They move out to 7 to 23 ft in summer and finish the year down in 7 to 23 ft. The spot to know is Deep basin, a deep basin in about 23 ft of water that rates prime for yellow perch in fall. Best bite is 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 | Go-to baits |
|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 7 to 23 ft | dawn | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 7 to 23 ft | midday | Jigging spoon (small), Perch rig / spreader |
| Winter | 7 to 23 ft | midday & dawn | Tungsten jig + spikes, Rattle spoon (small) |
Walleye fishing at Green Castle Lake
In spring, walleye run shallow here, mostly 4 to 15 ft. Summer pushes them deeper, 7 to 23 ft, and winter fish settle into 7 to 23 ft. Break off the point is the standout, a drop-off at roughly 9 ft, rated prime for fall walleye. Best bite is the evening and early morning. Tie on a crawler harness on bottom bouncer or a deep crankbait (trolled) and you're in the game.
| Season | Depth | Best window | Go-to baits |
|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | 1/8 oz jig + minnow, Hair jig |
| Summer | 7 to 23 ft | dusk & dawn | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 7 to 23 ft | dusk & night | Jigging rap, Jig + big minnow |
| Winter | 7 to 23 ft | dusk & dawn | Jigging spoon + minnow head, Rattle bait |
Notable structure
- Deep basin: deep basin, around 23 ft
- Break off the point: drop-off, around 9 ft
- Main-lake point: point, around 2 ft
- Shallow bay flat: weed flat, around 2 ft
Common questions
How deep is Green Castle Lake?
Green Castle Lake is about 23 ft at its deepest point. The depth chart here comes from real state fisheries GPS surveys, so the contours reflect measured depths.
What fish are in Green Castle Lake?
Anglers target largemouth bass, walleye, crappie, bluegill, channel catfish, yellow perch on Green Castle Lake.
Where is the best fishing spot on Green Castle Lake?
Deep basin is the top-rated area: a deep basin in about 23 ft of water that rates prime for crappie in winter. Open the map above to see every rated spot for each species and season.
When is the best time to fish Green Castle Lake?
For crappie, 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.
Nearby waters
Rock Creek Lake · Mariposa Lake · Arbor Lake · Union Grove Lake · Otter Creek Lake · Diamond Lake
See how Green Castle Lake stacks up: best largemouth bass lakes in Iowa · best walleye lakes in Iowa · best crappie lakes in Iowa · best bluegill lakes in Iowa
Browse all Iowa fishing maps or every water on DepthScout. Bathymetry credit: state fisheries survey programs. How we build these maps. For fishing guidance only, never navigation.