Minnesota · Douglas County
Union Lake Fishing guide
Union Lake is a 107-acre lake in Douglas County, Minnesota, reaching 45 ft at its deepest point. Average water clarity runs about 11.2 ft. The Minnesota DNR has surveyed the lake 10 times, most recently in 2022, with walleye, largemouth bass, northern pike and bluegill in the nets.
DNR survey data
Fish species
Largemouth bassGood numbers82per hr (electrofishing)11"Typical19"Biggest
Lengths measured · 90 fish
Recent · 2022Lengths measured · 90 fish
2022Lengths measured · 6 fish
2016Only 6 fish measured that year — too few to read as a shape.
Lengths measured · 40 fish
2010Lengths measured · 5 fish
2005Only 5 fish measured that year — too few to read as a shape.
Northern pikeJust a few5.5per gill net18"Typical27"Biggest
Lengths measured · 24 fish
Recent · 2022Lengths measured · 24 fish
2022Lengths measured · 63 fish
2016Lengths measured · 37 fish
2010Lengths measured · 58 fish
2005BluegillJust a few22.3per trap net5"Typical8"Biggest
Lengths measured · 241 fish
Recent · 2022Lengths measured · 241 fish
2022Lengths measured · 229 fish
2016Lengths measured · 233 fish
2010Lengths measured · 136 fish
2005CrappieJust a few2.2per trap net9"Typical13"Biggest
Lengths measured · 32 fish
Recent · 2022Lengths measured · 32 fish
2022Lengths measured · 31 fish
2016Lengths measured · 5 fish
2010Only 5 fish measured that year — too few to read as a shape.
Lengths measured · 35 fish
2005Rates come from standard DNR survey gear (gill nets, trap nets, electrofishing), judged against statewide benchmarks for the same gear, so the same number of fish per net can read differently for two species. Where the standard gear can't count a species reliably, only presence and size are listed. Typical is the middle fish of those measured. Open a row for the full length spread, survey by survey.
How to fish Union Lake through the year
Largemouth bass
- Spring
- Largemouth are moving up into the warming bays and flats, staging around wood, docks and new weeds to spawn. At 11.2 ft of clarity, fish them deeper and lighter than usual.
- Early summer
- Largemouth are on the shallow spawning flats and protected bays, where beds go on firm bottom next to isolated cover.
- Summer
- Largemouth are in and along the weeds: cabbage and milfoil edges, matted cover and shade. On a lake that drops to 45 ft, check the deep edge of that structure too.
- Fall
- Largemouth are chasing bait back onto the flats and into the remaining green weeds, feeding hard and shallow before the freeze.
Walleye
- Spring
- Walleye are shallow, on and just off the spawning flats and the first green weeds. At 11.2 ft of clarity, fish them deeper and lighter than usual.
- Early summer
- Walleye are setting up on the outside weed edge, points and shallow structure.
- Summer
- Walleye are working the weed edge, points and any wind-blown structure. On a lake that drops to 45 ft, check the deep edge of that structure too.
- Fall
- Walleye are packing onto the sharpest breaks and points as the water cools, in big schools with short windows.
Season patterns for each species. Open the live map for today's wind, light and water temp.
Size history
Biggest fish by survey year
| Survey year | Largemouth bass | Walleye | Northern pike |
|---|---|---|---|
| 2022 | 19" | 23" | 27" |
| 2016 | 14" | 21" | 31" |
| 2010 | 18" | 26" | 24" |
| 2005 | 14" | 26" | 30" |
| 2000 | 18" | 19" | 32" |
| 1995 | 19" | 24" | 32" |
Longest fish measured by DNR survey crews in each year's nets. Survey gear samples the population, so the lake usually holds larger fish than any survey measured.
Suggested tackle
What to bring
Top presentations for this lake's structure and clarity:
Largemouth bass · Soft plastics
Texas-Rigged Worm
7" ribbon-tail or straight-tail plastic worm
Largemouth bass · Soft plastics
Free Rig
Creature bait or magnum finesse worm
Walleye · Live bait
Live-Bait (Lindy) Rig + Leech/Crawler
jumbo leech or half a nightcrawler
Walleye · Trolling
Leadcore Line + Crankbaits
4–5" mid-diving crankbait behind a long leadcore run
Northern pike · Soft plastics
Paddletail Swimbait on Jighead
4–5" paddletail swimbait on a ball-head swimbait jighead
Northern pike · Muskie & pike
Soft Rubber (Bull Dawg / Medusa)
10" soft rubber body bait
Full setups, including hooks, weights and line, are on the live map. As an Amazon Associate I earn from qualifying purchases.
DNR stocking records
Stocking history
| Year | Species | Stocked |
|---|---|---|
| 2024 | Walleye | 1,140 fingerlings |
| 2023 | Walleye | 660 fingerlings |
| 2022 | Walleye | 1,311 fingerlings |
| 2019 | Walleye | 232 fingerlings |
MN DNR · in their words
From the 2022 survey
Union (also referred to as South Union) Lake is a small, bowl-shaped basin located between Alexandria and Forada. Water quality and clarity are good. Water transparency readings typically exceed 10 feet during summer months. A small, public access is located along the northeast shoreline. Union Lake contains a relatively simple fish community consistent with most bass-panfish lakes found in west-central Minnesota.
The Bluegill population (22.3/trap net) is similar to recent surveys. Recruitment is consistent, with many strong year classes. Growth is also fairly fast. Average and maximum length were almost 6 and 9 inches, respectively. Similar to other mid-July surveys, few Black Crappies were sampled. During the 2022 survey, Black Crappie abundance (2.8/gill net) while low, was a historical high for Union Lake. Average and maximum length were over 10 and 13 inches, respectively.
Read the full DNR narrative
Largemouth Bass relative abundance (82/hour of electrofishing) was substantially higher than the previous two surveys (34.2/hour in 2016 and 19.6/hour in 2010). Bass ranged in length from 3 to 19 inches, with a mean of 11.5 inches. Many bass were small but 34% exceeded 14 inches.
Northern Pike (5.5/gill net) were less abundant than they have been in the past. Size structure was poor (81% of pike were below 22 inches), similar to past surveys. Average length was slightly over 20 inches and the largest pike sampled was only 28 inches. Anglers are encouraged to harvest small Northern Pike. New Northern Pike regulations were implemented in 2018 to increase size structure. Union Lake is in the North-Central Zone, where all pike from 22 to 26 inches must be released. Anglers can keep 10 pike, but not more than two can be longer than 26 inches. Northern Pike taken by spearing follow the same rules except one pike may be between 22 and 26 inches, or two larger than 26 inches. For more information see: https://www.dnr.state.mn.us/pike/index.html.
Walleye (0.8/gill net) and Yellow Perch (0.3/gill net) were sampled at low densities, but this is similar to previous surveys. Walleye ranged in length from 19 to 23 inches. Too few of each species were sampled for any meaningful analysis. Other species sampled were Black Bullhead, Bowfin (Dogfish), Brown Bullhead, Hybrid Sunfish, Pumpkinseed and Yellow Bullhead.
Narrative text from the Minnesota DNR lake survey.
Recent reports
Union Lake fishing reports
Recent reports on Union Lake from guides, tournaments and regular anglers. Anything posted in the last two weeks also bumps the matching spots on the live map, so you'll see a "matches a recent report" tag on them.
Public water access
Getting on the water
- Union Lake (trailer launch)
DNR bathymetry
Union Lake depth map
Within 30 miles
Nearby lakes
- Lake Burgan · 174 ac · 2.2 mi
- Maple Lake · 831 ac · 3.3 mi
- Lake Jessie · 110 ac · 3.7 mi
- Lake Andrew · 923 ac · 3.8 mi
- Lake Victoria · 417 ac · 4 mi
- Turtle Lake · 218 ac · 4.1 mi
- Smith Lake · 666 ac · 5.1 mi
- Lake Winona · 213 ac · 5.1 mi
Quick answers
Frequently asked questions
How deep is Union Lake?
Union Lake reaches 45 ft at its deepest point with a mean depth of 14 ft; about 53% of the lake is littoral (15 ft or shallower).
How big is Union Lake?
Union Lake covers 107 acres with about 1.8 miles of shoreline.
How clear is the water in Union Lake?
DNR Secchi readings on Union Lake average 11.2 ft of visibility, clear water for a Minnesota lake.
What fish are in Union Lake?
Minnesota DNR surveys (most recently 2022) record walleye, largemouth bass, northern pike, bluegill, crappie, yellow perch.
Is Union Lake stocked?
Yes. The DNR stocked walleye in 2024; the stocking table on this page lists every year back to 2019.
Does Union Lake have a public access?
Yes. Union Lake has one public access site: Union Lake (trailer launch).
How big do largemouth bass get in Union Lake?
The biggest largemouth bass measured in recent DNR surveys taped 19"; the size-history table on this page tracks the biggest fish in each survey back to 1995.
When was Union Lake last surveyed?
The Minnesota DNR last surveyed Union Lake in 2022, the most recent of 10 surveys on record.
Page updated .
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