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Fishing Harmon Lake: what the data says
140-acre lake near Mandan. The lake tops out around 45 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. What follows comes from the same scoring engine that paints the spots above.
Largemouth Bass fishing at Harmon Lake
In spring, largemouth bass run shallow here, mostly 2 to 10 ft. Summer pushes them deeper, 8 to 20 ft, and winter fish settle into 15 to 35 ft. Shallow bay flat is the standout, a weed flat at roughly 7 ft, rated prime for spring largemouth bass. 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 | 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 | 15 to 35 ft | midday | Blade bait, Jigging spoon |
Bluegill fishing at Harmon Lake
Spring bluegill on Harmon 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. Back-bay flat is the standout, a weed flat at roughly 3 ft, rated prime for spring bluegill. Best bite is early morning and the evening. Summer baits: a small sponge spider (fly) or a micro tube jig gets it done.
| 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 | 10 to 25 ft | midday | Tungsten ice jig + plastic, Tiny spoon |
Northern Pike fishing at Harmon Lake
In spring, northern pike run shallow here, mostly 2 to 8 ft. Summer pushes them deeper, 8 to 20 ft, and winter fish settle into 5 to 15 ft. Shallow bay flat is the standout, a weed flat at roughly 7 ft, rated prime for spring northern pike. Best bite is 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 | Go-to baits |
|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Tip-ups, Large jigging spoon |
Crappie fishing at Harmon Lake
Start shallow in spring: crappie sit in 2 to 8 ft that time of year. They move out to 10 to 25 ft in summer and finish the year down in 15 to 35 ft. If you only fish one area, make it Deep basin: a deep basin around 37 ft that scores prime in winter. Best bite is early morning and the evening. A jig trolled/spider-rigged or a small crankbait (trolled) covers the summer program.
| Season | Depth | Best window | Go-to baits |
|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | 1/16 oz jig + tube, Curly-tail grub |
| Summer | 10 to 25 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 | 15 to 35 ft | midday | Tungsten jig + soft plastic, Tiny jigging spoon |
Channel Catfish fishing at Harmon Lake
In spring, channel catfish run shallow here, mostly 3 to 12 ft. Summer pushes them deeper, 8 to 25 ft, and winter fish settle into 20 to 40 ft. Deep basin is the standout, a deep basin at roughly 37 ft, rated prime for winter channel catfish. Best bite is after dark and the evening.
| Season | Depth | Best window | Go-to baits |
|---|---|---|---|
| Spring | 3 to 12 ft | dusk | |
| Summer | 8 to 25 ft | night & dusk | |
| Fall | 10 to 30 ft | dusk | |
| Winter | 20 to 40 ft | midday |
Notable structure
- Deep basin: deep basin, around 37 ft
- Secondary point: point, around 11 ft
- Break off the point: drop-off, around 8 ft
- Shallow bay flat: weed flat, around 7 ft
- Main-lake point: point, around 6 ft
- Back-bay flat: weed flat, around 3 ft
Common questions
How deep is Harmon Lake?
Harmon Lake is about 45 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 Harmon Lake?
Anglers target largemouth bass, northern pike, crappie, bluegill, channel catfish on Harmon Lake.
Where is the best fishing spot on Harmon Lake?
Shallow bay flat is the top-rated area: a weed flat in about 7 ft of water that rates prime for largemouth bass in spring. Open the map above to see every rated spot for each species and season.
When is the best time to fish Harmon Lake?
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.
Nearby waters
Missouri River · Nelson Lake · Sweet Briar Lake · McDowell Dam · West Park Lake · East Park Lake
See how Harmon Lake stacks up: best largemouth bass lakes in North Dakota · best northern pike lakes in North Dakota · best crappie lakes in North Dakota · best bluegill lakes in North Dakota
Browse all North Dakota fishing maps or every water on DepthScout. Bathymetry credit: state fisheries survey programs. How we build these maps. For fishing guidance only, never navigation.