Olson Lake (Cook County)
Cook County, Minnesota - DNR stocking history, depth and survey data
Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 16015800
DNR records show 10 stocking entries at Olson Lake (Cook County) since 2016, most recently rainbow trout fingerlings in 2025 (1,500 fish).
- Olson Lake (Cook County) has 10 DNR stocking records across 10 years (2016-2025): rainbow trout (10).
- The most-stocked species by count is rainbow trout: 16,011 fish on record.
- Maximum depth 18 ft, mean depth 6 ft; surface area 34 acres, 34 littoral acres, 1.3 miles of shoreline, per the DNR lake survey.
- Average water clarity (Secchi depth) 6.3 ft.
- Fish species DNR lists here: rainbow trout.
- 1 public access on the DNR list.
- Most recent DNR fish survey: (standard survey).
- Cook County, nearest town Grand Marais; DNR lake number (DOW) 16015800.
Stocking history
| Year | Species | Size | Number | Pounds |
|---|---|---|---|---|
| 2025 | Rainbow Trout | fingerlings | 1,500 | 120.0 |
| 2024 | Rainbow Trout | fingerlings | 1,500 | 150.0 |
| 2023 | Rainbow Trout | fingerlings | 1,500 | 115.4 |
| 2022 | Rainbow Trout | fingerlings | 1,500 | 93.8 |
| 2021 | Rainbow Trout | fingerlings | 1,500 | 250.0 |
| 2020 | Rainbow Trout | fingerlings | 1,511 | 329.9 |
| 2019 | Rainbow Trout | fingerlings | 1,500 | 125.0 |
| 2018 | Rainbow Trout | fingerlings | 2,500 | 208.3 |
| 2017 | Rainbow Trout | fingerlings | 1,500 | 81.1 |
| 2016 | Rainbow Trout | fingerlings | 1,500 | 100.0 |
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 |
|---|---|---|
| CA | Minnesota DNR | Short carry-down off the end of a logging road from Two Island Lake USFS campground to the north end of Olson Lake. - Logging road grown up, becoming very narrow. |
DNR fish survey, 2025
| Species | Gear | Catch per net | Total catch | Avg lb |
|---|---|---|---|---|
| Rainbow trout | Standard gill nets | 1.50 | 3 | 1.58 |
| Rainbow trout | Standard trap nets | 0.25 | 2 | 0.80 |
| Pearl dace | Standard trap nets | 0.12 | 1 | 0.00 |
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.
Olson Lake is a small, 34-acre lake located in Cook County, Minnesota. It has been managed exclusively for stream trout since it was reclaimed in 1961. Currently, Olson Lake is stocked annually with 1,500 Arlee-strain rainbow trout fingerlings during the fall. The 2018 lake management plan established a long-range goal to maintain a minimum rainbow trout trap net catch of 0.75 fish/net, with some fish over 14 inches present. In 2025, a standard survey was conducted on Olson Lake using standard gillnets and trap nets to assess the current fish community. Catch rates of rainbow trout were low in both gill nets (1.5 fish/net) and trap nets (0.25 fish/net) in the 2025 survey and lower than previous catch rates observed in 2008 when brook trout were stocked. Only five rainbow trout were caught and ranged from 13.0 to 19.3 inches, with only one fish exceeding 14.0 inches. Age analysis found two- and three-year-old fish, from the 2023 and 2022 stocked year classes. Age two rainbow trout averaged 12.8 inches and the only three-year-old fish caught was remarkably 19.3 inches. Trap nets did not find any numbers or sizes of minnows and may indicate a lack of forage within the lake. Anglers looking to target rainbow trout in Olson Lake will have their best luck during the fall and winter months when fish are more readily available from stocking. A water temperature and dissolved oxygen profile taken in late July found unsuitable conditions for rainbow trout. Surface waters to depths of 6.0 ft were too warm (> 70°F) while depths from 6.0 to 14.0 ft were depleted of oxygen ( Minnesota Lakes within Cook County continue to be susceptible to aquatic invasive species introductions. Invasive species have the potential to significantly alter fish communities and overall lake health. Anglers should clean watercraft and fishing gear, drain all water, and dispose of unused bait in the trash to prevent accidental introductions.
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. Regulations, slot limits and special rules are on the DNR page linked above, not here.
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