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689-acre lake in Rainy River District, Ontario. The lake tops out around 46 ft. The depth chart comes from Ontario Ministry of Natural Resources and Forestry bathymetric survey data, so the contours are survey-derived rather than computer-modeled. The depth data here comes from a transect sounding survey by the Ontario MNRF. The rest of this page walks each species through its year, using the map's own scoring.
Drawn out, this is 692 acres of water rimmed by 12.8 miles of bank, with 7 islands in the mix. The 3.5 development index tells the story — a convoluted bank whose fishable edge far outruns the acreage. About 75% of the surface sits shallower than 15 ft — that's the weed-and-bait zone. The basin spans about 2.9 mi end to end and 1.2 mi across at its widest. The water lies in Rainy River District. The nearest mapped water is Chief Peter Lake, 4 mi to the southeast.
These fish are listed in an exact-water agency record as forage or ecological context. They are not target-species profiles and do not affect DepthScout's Prime, Good, or Fair spot ratings.
Official Ontario MNRF Fish ON-Line record. The listing documents source-recorded presence, not present abundance or guaranteed catchability.
Come spring, look for lake whitefish tight to the bank in 15 to 45 ft. Expect a summer slide to 14 to 46 ft, then a winter hold in 14 to 46 ft. Start at Deep basin. It's a deep basin holding about 46 ft of water and rates prime come summer. Prime time lands in early morning. A blade bait vertical or a small jigging spoon is the honest summer answer here.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 15 to 45 ft | midday & dawn | Break off the point (13 ft) | Small jig + waxworm, Blade bait (small) |
| Summer | 14 to 46 ft chart-limited; documented 40 to 90 ft | dawn | Deep basin (46 ft) | Blade bait vertical, Small jigging spoon |
| Fall | 8 to 30 ft | dusk | Break off the point (13 ft) | Small spoon (gold), Jig + plastic larva |
| Winter | 14 to 46 ft chart-limited; documented 25 to 70 ft | midday & dawn | Deep basin (46 ft) | Jigging spoon + bead chain, Tungsten jig + waxie |
Come spring, look for cisco (lake herring) tight to the bank in 10 to 40 ft. Expect a summer slide to 14 to 46 ft, then a winter hold in 14 to 46 ft. Start at Deep basin. It's a deep basin holding about 46 ft of water and rates prime come summer. Prime time lands in early morning. A vertical flutter spoon (small) or a drop-shot micro plastic is the honest summer answer here.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 10 to 40 ft | dawn & dusk | Deep basin (46 ft) | Small silver spoon, Tiny swim jig (white) |
| Summer | 14 to 46 ft chart-limited; documented 40 to 80 ft | dawn | Deep basin (46 ft) | Vertical flutter spoon (small), Drop-shot micro plastic |
| Fall | 5 to 25 ft | dusk & dawn | Break off the point (13 ft) | Small casting spoon, Inline spinner (silver) |
| Winter | 14 to 46 ft chart-limited; documented 20 to 60 ft | dawn | Deep basin (46 ft) | Small jigging spoon (glow/silver), Tungsten jig + minnow head |
Spring walleye on Union Lake hold shallow, usually 4 to 15 ft. They move out to 15 to 35 ft in summer and finish the year down in 20 to 40 ft. Put Break off the point first on the milk run — a drop-off near 13 ft that grades prime for fall. The feeding windows run the evening and early morning. The summer box starts with a crawler harness on bottom bouncer or a deep crankbait (trolled).
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 4 to 15 ft | dusk & dawn | Break off the point (13 ft) | 1/8 oz jig + minnow, Hair jig |
| Summer | 15 to 35 ft | dusk & dawn | Break off the point (13 ft) | Crawler harness on bottom bouncer, Deep crankbait (trolled) |
| Fall | 12 to 40 ft | dusk & night | Break off the point (13 ft) | Jigging rap, Jig + big minnow |
| Winter | 20 to 40 ft | dusk & dawn | Deep basin (46 ft) | Jigging spoon + minnow head, Rattle bait |
Early season yellow perch use the shallows, holding in 3 to 12 ft. Expect a summer slide to 10 to 30 ft, then a winter hold in 15 to 35 ft. Put Break off the point first on the milk run — a drop-off near 13 ft that grades prime for summer. In summer the feeding windows fall in 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 | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Back-bay flat (2 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 10 to 30 ft | dawn | Break off the point (13 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 12 to 35 ft | midday | Break off the point (13 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 15 to 35 ft | midday & dawn | Shallow feeding flat (15 ft) | Tungsten jig + spikes, Rattle spoon (small) |
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. Back-bay flat is the standout, a weed flat at roughly 2 ft, rated prime for spring northern pike. Time it for early morning and the evening. You won't need more than a bucktail or a weedless spoon over cabbage most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 8 ft | midday & dawn | Back-bay flat (2 ft) | #5 inline spinner, Spoon (red/white) |
| Summer | 8 to 20 ft | dawn & dusk | Break off the point (13 ft) | Bucktail, Weedless spoon over cabbage |
| Fall | 6 to 18 ft | midday & dawn | Break off the point (13 ft) | Big rubber (Bull Dawg style), Husky-style jerkbait |
| Winter | 5 to 15 ft | midday | Shallow feeding flat (15 ft) | Tip-ups, Large jigging spoon |
The spring pattern is a shallow one: burbot in 14 to 46 ft. The depth story barely changes: 14 to 46 ft through summer, 12 to 46 ft in winter. Top water on the chart: Deep basin, a deep basin in the 46 ft range, prime in spring. Time it for after dark and midday. Summer baits: a heavy jig + cut bait gets it done.
Depth note: when a documented seasonal range extends below this chart, the table shows the deepest mapped working water, not a verified holding depth.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 14 to 46 ft chart-limited; documented 25 to 70 ft | night & dusk | Deep basin (46 ft) | Glow jigging spoon + cut bait, Rattle bait (dark) |
| Summer | 14 to 46 ft chart-limited; documented 50 to 120 ft | night & midday | Deep basin (46 ft) | Heavy jig + cut bait |
| Fall | 14 to 46 ft chart-limited; documented 30 to 80 ft | night & dusk | Deep basin (46 ft) | Glow spoon + minnow head, Blade bait (slow) |
| Winter | 12 to 46 ft chart-limited; documented 15 to 60 ft | night & dusk | Deep basin (46 ft) | Glow tungsten + cut bait, Rattle spoon + minnow head |
The chart marks 7 structure features on Union Lake; the deepest is Deep basin at about 46 ft.
Access data: Geospatial Ontario - Fishing Access Points; Government of Ontario - MNR Unpatented Crown Land Shoreline; Government of Ontario - MNR Unpatented Crown Land Shoreline. Confirm conditions and fees locally before you launch.
Season dates, license requirements, and size and bag limits for Ontario waters are set by the Ontario fishing regulations (FMZ summary) — and special regulations can apply to Union Lake specifically, so confirm the current rules before you fish.
Check the official Ontario fishing regulations →
Union Lake is about 46 ft (14 m) deep at its deepest point. The depth data here comes from a transect sounding survey by the Ontario MNRF.
Anglers target lake whitefish, cisco (lake herring), walleye, yellow perch, northern pike, burbot on Union Lake.
Deep basin is the top-rated area: a deep basin in about 46 ft of water that rates prime for lake whitefish in summer. Scroll up to the map for the complete spot list by species and season.
For lake whitefish, the summer bite is best in 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 Ontario fishing regulations (FMZ summary). Check the official Ontario regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Chief Peter Lake 4 mi · Mercutio Lake 5 mi · Edar Lake 6 mi · Elbow Lake 6 mi · Burnt Island Lake 6 mi · Crooked Pine Lake 7 mi · Bedivere Lake 7 mi · Nydia Lake 8 mi · Windigoostigwan Lake 8 mi · Lance Lake 9 mi · Brûlé Lake 9 mi · Upham Lake 10 mi
See how Union Lake stacks up: best walleye lakes in Ontario · best northern pike lakes in Ontario · best yellow perch lakes in Ontario · best lake whitefish lakes in Ontario
More water nearby: Rainy River District fishing maps (257 charts). Browse all Ontario fishing maps. See every water on DepthScout. Bathymetry: published agency survey data. 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.