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474-acre lake near Commerce Twp. The lake tops out around 110 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. Species by species, here's what the data says the year looks like.
Come spring, look for smallmouth bass tight to the bank in 3 to 12 ft. Expect a summer slide to 10 to 30 ft, then a winter hold in 20 to 45 ft. Start at Break off the point. It's a drop-off holding about 37 ft of water and rates prime come winter. Prime time lands in early morning and the evening. A drop shot (goby/minnow) or a ned rig is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dawn & dusk | Main-lake point (1 ft) | Ned rig, Tube jig |
| Summer | 10 to 30 ft | dawn & dusk | Break off the point (37 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 8 to 25 ft | midday & dawn | Main-lake point (1 ft) | Jerkbait, Blade bait |
| Winter | 20 to 45 ft | midday | Break off the point (37 ft) | Blade bait, Hair jig |
When the water first warms, largemouth bass slide up into 2 to 10 ft. By summer they slide out to 8 to 20 ft, and by winter most fish are in 15 to 35 ft. If you only fish one area, make it Break off the point: a drop-off around 37 ft that scores prime in winter. In summer the feeding windows fall in 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 (1 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Shallow bay flat (1 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (1 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 15 to 35 ft | midday | Break off the point (37 ft) | Blade bait, Jigging spoon |
When the water first warms, bluegill slide up into 1 to 6 ft. Summer is a 4 to 15 ft game here, winter a 10 to 25 ft one. Start at Shallow bay flat. It's a weed flat holding about 1 ft of water and rates prime come spring. The feeding windows run 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 | Shallow bay flat (1 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow bay flat (1 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Shallow bay flat (1 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 10 to 25 ft | midday | Deep basin (110 ft) | Tungsten ice jig + plastic, Tiny spoon |
Count 8 structure marks on this chart. The deepest, Deep basin, sits near 110 ft.
Access data: Michigan DNR — Michigan Boating Access Sites. Confirm conditions and fees locally before you launch.
Season dates, license requirements, and size and bag limits for Michigan waters are set by the Michigan DNR — and special regulations can apply to Union Lake specifically, so confirm the current rules before you fish.
Check the official Michigan fishing regulations →
Union Lake is about 110 ft (34 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 smallmouth bass, largemouth bass, bluegill on Union Lake.
Break off the point is the top-rated area: a drop-off in about 37 ft of water that rates prime for smallmouth bass in winter. The map above holds the full rated-spot list for every species and season.
For smallmouth 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 Union Lake is regulated by the Michigan DNR. Check the official Michigan regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Long Lake 1 mi · Middle Straits Lake 2 mi · Lower Straits Lake 2 mi · Carroll Lake 2 mi · Pleasant Lake 2 mi · Cedar Island Lake 3 mi · Elizabeth Lake 3 mi · Cass Lake 3 mi · Sugden Lake 3 mi · Orchard Lake 3 mi · South Commerce Lake 4 mi · Oxbow Lake 4 mi
See how Union Lake stacks up: best largemouth bass lakes in Michigan · best smallmouth bass lakes in Michigan · best bluegill lakes in Michigan
More water nearby: Oakland County fishing maps (78 charts). Browse all Michigan 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.