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1,292-acre lake near Branch County. The lake tops out around 16 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. The rest of this page walks each species through its year, using the map's own scoring.
The drawn outline gives you 7 miles of bank to pick apart. The shoreline is moderately structured (index 2.1) — enough points and pockets to pattern. The basin spans about 2.7 mi end to end and 0.6 mi across at its widest. The water lies in Branch County. The nearest mapped water is Oliverda Lake, 4 mi to the west.
When the water first warms, walleye slide up into 4 to 15 ft. Summer is a 5 to 16 ft game here, winter a 5 to 16 ft one. Start at Deep basin. It's a deep basin holding about 14 ft of water and rates prime come winter. The feeding windows run the evening and early morning. Keep a crawler harness on bottom bouncer or a deep crankbait (trolled) rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | Main-lake point (4 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 5 to 16 ft | dusk & dawn | Secondary point (6 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 5 to 16 ft | dusk & night | Secondary point (6 ft) | Jigging rap, Jig + big minnow |
| Winter | 5 to 16 ft | dusk & dawn | Deep basin (14 ft) | Jigging spoon + minnow head, Rattle bait |
When the water first warms, yellow perch slide up into 3 to 12 ft. By summer they slide out to 5 to 16 ft, and by winter most fish are in 5 to 16 ft. If you only fish one area, make it Shallow bay flat: a weed flat around 3 ft that scores prime in spring. In summer the feeding windows fall in early morning. Keep a drop-shot micro plastics or a small spoon tipped with worm rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (3 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 5 to 16 ft | dawn | Deep basin (14 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 5 to 16 ft | midday | Deep basin (14 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 5 to 16 ft | midday & dawn | Deep basin (14 ft) | Tungsten jig + spikes, Rattle spoon (small) |
The spring pattern is a shallow one: northern pike in 2 to 8 ft. As the season builds they drop to 5 to 16 ft, wintering in 5 to 15 ft. Top water on the chart: Shallow bay flat, a weed flat in the 3 ft range, prime in spring. Time it for early morning and the evening. Summer baits: a bucktail or a weedless spoon over cabbage gets it done.
| 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 | 5 to 16 ft | dawn & dusk | Back-bay flat (5 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 5 to 16 ft | midday & dawn | Back-bay flat (5 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Back-bay flat (5 ft) | Tip-ups, Large jigging spoon |
Spring puts muskellunge in skinny water — 3 to 12 ft is the zone. As the season builds they drop to 5 to 16 ft, wintering in 5 to 16 ft. Spring muskellunge concentrate at Shallow bay flat, a prime-rated weed flat around 3 ft. Warm-month bites cluster around the evening and early morning. A double-10 bucktail or a topwater (walk-the-dog / creeper) covers the summer program.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dusk | Shallow bay flat (3 ft) | Smaller bucktail (#8 blades), 6" glide bait |
| Summer | 5 to 16 ft | dusk & dawn | Secondary point (6 ft) | Double-10 bucktail, Topwater (walk-the-dog / creeper) |
| Fall | 4 to 16 ft | midday & dusk | Main-lake point (4 ft) | Big rubber (Bull Dawg style), 10"+ glide bait |
| Winter | 5 to 16 ft | midday | Deep basin (14 ft) | Large rubber, crawled slow |
The spring pattern is a shallow one: smallmouth bass in 3 to 12 ft. As the season builds they drop to 5 to 16 ft, wintering in 5 to 16 ft. Top water on the chart: Secondary point, a point in the 6 ft range, prime in fall. Time it for early morning and the evening. Summer baits: a drop shot (goby/minnow) or a ned rig gets it done.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dawn & dusk | Main-lake point (4 ft) | Ned rig, Tube jig |
| Summer | 5 to 16 ft | dawn & dusk | Secondary point (6 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 5 to 16 ft | midday & dawn | Secondary point (6 ft) | Jerkbait, Blade bait |
| Winter | 5 to 16 ft | midday | Deep basin (14 ft) | Blade bait, Hair jig |
Start shallow in spring: largemouth bass sit in 2 to 10 ft that time of year. Summer pushes them deeper, 5 to 16 ft, and winter fish settle into 5 to 16 ft. The spot to know is Shallow bay flat, a weed flat in about 3 ft of water that rates prime for largemouth bass in spring. Warm-month bites cluster around early morning and the evening. Throw a texas-rigged 10" worm or a deep-diving crankbait until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (3 ft) | Spinnerbait, Chatterbait |
| Summer | 5 to 16 ft | dawn & dusk | Back-bay flat (5 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (4 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 5 to 16 ft | midday | Deep basin (14 ft) | Blade bait, Jigging spoon |
Union Lake also holds crappie (5 to 16 ft in summer), bluegill (4 to 15 ft in summer), channel catfish (5 to 16 ft in summer). Pick any of them on the map above for rated spots and bait picks.
Count 5 structure marks on this chart. The deepest, Deep basin, sits near 14 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 16 ft (5 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 walleye, yellow perch, northern pike, muskellunge, smallmouth bass, largemouth bass, crappie, bluegill, channel catfish on Union 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.
Deep basin is the top-rated area: a deep basin in about 14 ft of water that rates prime for walleye in winter. Scroll up to the map for the complete spot list by species and season.
For walleye, the summer bite is best in the evening and 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 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.
Oliverda Lake 4 mi · Turtle Lake 5 mi · Goodrich Lake 7 mi · Havens Lake 7 mi · Morrison Lake 9 mi · Lee Lake 9 mi · Randall Lake 9 mi · Warner Lake 9 mi · Palmer Lake 10 mi · South Lake 11 mi · Cary Lake 11 mi · Graham Lake 12 mi
See how Union Lake stacks up: best largemouth bass lakes in Michigan · best smallmouth bass lakes in Michigan · best walleye lakes in Michigan · best northern pike lakes in Michigan
More water nearby: Branch County fishing maps (14 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.