Sign inSign up free Sign inSign up free Sign inSign up freeShared by DepthScout anglers. Exact spots stay private, always.
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. Every species below gets its seasonal read from the same numbers driving the chart.
Harmon Lake maps at 137 acres behind 4.9 miles of shoreline. An index of 3 puts the bank firmly in maze territory: point after pocket after cove, every one a casting target. Littoral water — the productive band under ~15 ft — makes up 39% of this chart. The basin spans about 0.9 mi end to end and 0.8 mi across at its widest. It sits in Morton County. Its nearest charted neighbour, Sweet Briar Lake, is 15 mi to the west.
When the water first warms, largemouth bass slide up into 2 to 10 ft. Summer is an 8 to 20 ft game here, winter a 15 to 35 ft one. Start at Shallow bay flat. It's a weed flat holding about 7 ft of water and rates prime come spring. The feeding windows run early morning and the evening. Keep a texas-rigged 10" worm or a deep-diving crankbait rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (7 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Shallow bay flat (7 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 | 15 to 35 ft | midday | Break off the point (3 ft) | Blade bait, Jigging spoon |
When the water first warms, bluegill slide up into 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. If you only fish one area, make it Back-bay flat: a weed flat around 2 ft that scores prime in spring. In summer the feeding windows fall in early morning and the evening. Keep a small sponge spider (fly) or a micro tube jig rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | Back-bay flat (2 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow bay flat (7 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Shallow bay flat (7 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 10 to 25 ft | midday | Shallow bay flat (7 ft) | Tungsten ice jig + plastic, Tiny spoon |
Come spring, look for northern pike tight to the bank in 2 to 8 ft. They move out to 8 to 20 ft in summer and finish the year down in 5 to 15 ft. If you only fish one area, make it Shallow bay flat: a weed flat around 7 ft that scores prime in spring. Best bite is early morning and the evening. A bucktail or a weedless spoon over cabbage is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (7 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Shallow bay flat (7 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Shallow bay flat (7 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow bay flat (7 ft) | Tip-ups, Large jigging spoon |
Come spring, look for crappie tight to the bank in 2 to 8 ft. 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 Shallow bay flat: a weed flat around 7 ft that scores prime in spring. Best bite is early morning and the evening. A jig trolled/spider-rigged or a small crankbait (trolled) is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Shallow bay flat (7 ft) | 1/16 oz jig + tube, Curly-tail grub |
| Summer | 10 to 25 ft | dawn & dusk | Shallow bay flat (7 ft) | Jig trolled/spider-rigged, Small crankbait (trolled) |
| Fall | 8 to 20 ft | dawn | Shallow bay flat (7 ft) | Jig + minnow combo, Small swimbait (1.5-2") |
| Winter | 15 to 35 ft | midday | Deep basin (43 ft) | Tungsten jig + soft plastic, Tiny jigging spoon |
When the water first warms, channel catfish slide up into 3 to 12 ft. Summer is an 8 to 25 ft game here, winter a 20 to 40 ft one. Start at Deep basin. It's a deep basin holding about 43 ft of water and rates prime come winter. The feeding windows run after dark and the evening.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dusk | Shallow bay flat (7 ft) | |
| Summer | 8 to 25 ft | night & dusk | open water | |
| Fall | 10 to 30 ft | dusk | Deep basin (43 ft) | |
| Winter | 20 to 40 ft | midday | Deep basin (43 ft) |
Structure-wise the chart holds 6 features, led in depth by Deep basin at roughly 43 ft.
Access data: North Dakota Game & Fish — Fishing Facilities. Confirm conditions and fees locally before you launch.
Season dates, license requirements, and size and bag limits for North Dakota waters are set by the North Dakota Game and Fish — and special regulations can apply to Harmon Lake specifically, so confirm the current rules before you fish.
Check the official North Dakota fishing regulations →
Harmon Lake is about 45 ft (14 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, bluegill, northern pike, crappie, channel catfish 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. 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 Harmon Lake is regulated by the North Dakota Game and Fish. Check the official North Dakota regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Sweet Briar Lake 15 mi · Missouri River 15 mi · Nelson Lake 16 mi · McDowell Dam 17 mi · Danzig Dam 30 mi · New Johns Lake 31 mi · West Park Lake 31 mi · Heckers Lake 31 mi · East Park Lake 31 mi · Coal Lake 35 mi · Crimmins WPA 38 mi · Lake Holmes 42 mi
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 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.