Union Lake (Polk County)
Polk County, Minnesota - DNR stocking history, depth and survey data
Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 60021700
DNR records show 5 stocking entries at Union Lake (Polk County) since 2016, most recently walleye fry in 2024 (591,000 fish).
- Union Lake (Polk County) has 5 DNR stocking records across 5 years (2016-2024): walleye (5).
- The most-stocked species by count is walleye: 2,956,000 fish on record.
- Maximum depth 83 ft; surface area 887 acres, 394 littoral acres, 14.6 miles of shoreline, per the DNR lake survey.
- Average water clarity (Secchi depth) 6.9 ft.
- Fish species DNR lists here: black bullhead, black crappie, bluegill, brown bullhead, common carp, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow perch.
- 1 public access on the DNR list.
- Most recent DNR fish survey: (standard survey).
- Polk County, nearest town Erskine; DNR lake number (DOW) 60021700.
Depth map
Bathymetric contours from the Minnesota DNR lake survey mapped 7/8/1969 (orig map); depths in feet. Simplified for the web; not for navigation.
Stocking history
| Year | Species | Size | Number | Pounds |
|---|---|---|---|---|
| 2024 | Walleye | fry | 591,000 | 5.5 |
| 2022 | Walleye | fry | 591,000 | 5.2 |
| 2021 | Walleye | fry | 592,000 | 5.2 |
| 2018 | Walleye | fry | 591,000 | 5.1 |
| 2016 | Walleye | fry | 591,000 | 5.1 |
Field note · Minnesota stocks by year, not by truck day: walleye fry go in within weeks of ice-out, fingerlings and yearlings mostly in fall, and stream trout in spring and fall. A row here means the fish went in during that year; DNR adds the year's rows after the fact, so the current year can look empty until winter.
Public accesses
| Type | Owner | Where |
|---|---|---|
| asphalt ramp | Minnesota DNR |
DNR fish survey, 2022
| Species | Gear | Catch per net | Total catch | Avg lb |
|---|---|---|---|---|
| Bluegill | Standard gill nets | 36.67 | 330 | 0.25 |
| Northern pike | Standard gill nets | 11.89 | 107 | 2.35 |
| Walleye | Standard gill nets | 6.33 | 57 | 3.08 |
| Black crappie | Standard gill nets | 5.22 | 47 | 0.24 |
| Common carp | Standard gill nets | 4.11 | 37 | 1.75 |
| Yellow perch | Standard gill nets | 4.11 | 37 | 0.08 |
| Largemouth bass | Standard gill nets | 1.78 | 16 | 0.99 |
| Pumpkinseed | Standard gill nets | 0.78 | 7 | 0.11 |
| Bluegill | Standard trap nets | 8.33 | 100 | 0.18 |
| Black crappie | Standard trap nets | 3.58 | 43 | 0.34 |
| Northern pike | Standard trap nets | 1.00 | 12 | 2.49 |
| Walleye | Standard trap nets | 0.58 | 7 | 2.25 |
| Pumpkinseed | Standard trap nets | 0.33 | 4 | 0.10 |
| Black bullhead | Standard trap nets | 0.17 | 2 | 1.13 |
| Common carp | Standard trap nets | 0.17 | 2 | 3.73 |
| Yellow perch | Standard trap nets | 0.08 | 1 | 0.09 |
Catch per net (CPUE) is the DNR survey's count per gill net or trap net set; higher means more of that species were sampled, not a fishing forecast. Top species per gear shown; where we have no verified common name for a DNR code, the code itself is shown.
Union Lake is an 887-acre lake located in south central Polk County. The lake has a history of large fluctuations in water levels, which are influenced primarily by ground water. The most recent water level rises in the late 1990's resulted in the formation of a lake improvement district (LID) made up of riparian owners on both Sarah and Union lakes. The LID facilitated construction of a pumped outlet to the Sand Hill River watershed, following property damage along the lake's shoreline. A standard fisheries survey was conducted in early August 2022 to assess the fish populations at Union Lake. Following a record high abundance of Walleye in 2012, Walleye gill net catch rates have declined in recent years. However, the 2022 catch rate of 6.3 Walleye per gill net is only slightly below the lake's historical average of 6.8 per net. Lengths of sampled Walleye ranged from 7.7 to 30.1 inches with an average of 19.0 inches. The Northern Pike gill net catch rate set a record high in 2022 at 11.9 fish per net. The historic average is 6.1 fish per net. Sampled Northern Pike ranged from 15.1 to 32.0 inches with an average of 21.9 inches. About 23% of the fish sampled were over 24 inches in length. The trap net catch of Bluegill was well below average in 2022 with a catch rate of 8.3 Bluegills per net. The historical average for the lake is 36.6 per net. These fish averaged 6.0 inches in length and ranged from 3.3 to 8.4 inches. Black Crappie abundance increased slightly from recent surveys with trap nets capturing 3.6 per net. Black Crappie sampled in trap nets had an average size of 8.7 inches, but individuals up to 12.1 inches long were encountered. Gill nets caught Largemouth Bass at 1.8 fish per net. Largemouth Bass averaged 11.5 inches long, with Largemouth Bass up to 18.1 inches long measured. Yellow Perch abundance was low in 2022, with fish having an average length of 6.3 inches. Trap net catches of Common Carp were similar to past surveys, but gill nets captured a record number of fish in 2022. Other fish species sampled in 2022 included Black and Brown Bullhead, Pumpkinseed, and White Sucker.
Minnesota DNR survey narrative, .
All Minnesota stockings · every Minnesota lake with a page · state CSV · this lake on DNR LakeFinder
Stocking rows, depths, accesses and survey figures are Minnesota DNR LakeFinder data as of 2026-09-02; contours are the DNR bathymetric survey. Regulations, slot limits and special rules are on the DNR page linked above, not here.
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