Leo

Leo Lake is a 102-acre lake with a maximum depth of 28.0 ft and located approximately 30 miles north of Grand Marais in Cook County, Minnesota. Access to the lake requires a steep, short carry-down off the Hungry Jack Lake Road. Leo Lake has been managed for stream trout since the 1930's, with rainbow trout stocked exclusively since 2007. The current stocking plan calls for 3,000 yearlings (Kamloops-strain) to be stocked in the spring annually. The 2025 survey was the first of three surveys scheduled in the 2022 lake management plan to determine whether the Kamloops-strain yearlings would be more successful at attaining better size and age structure within Leo Lake. In 2025, a standard survey was conducted using standard gillnets and trap nets to assess the current rainbow trout population in Leo Lake. Rainbow trout catch rates substantially increased from the 2015 survey to 12.0 fish/net in 2025 and were above the long-term average for the lake. Rainbow trout lengths ranged from 11.9 and 17.1 inches with an average size of 13.4 inches. Most of the rainbow trout captured were one-year-old fish (81%) and averaged 13.0 inches in size. A few two-year-old fish were also captured during the survey, averaging 15.8 inches in size, and were from the 2024 stocking event. Based on the two age classes present during the survey, growth rates appeared to be average for the lake. These results suggest Kamloops-strain rainbow trout may have grown better than the Arlee-strain, but survey data still does not show many older fish within the population. Temperature and dissolved oxygen profiles in August 2025 indicated poor habitat conditions for trout, with only depths between 15.0 and 19.0 feet supporting cold and oxygenated water for stream trout during the summer time. Habitat conditions improved in September with suitable water temperatures and oxygen levels present from the surface down to depths of 22.0 feet. Although habitat is marginal for stream trout in Leo Lake during the summertime, rainbow trout are still able to persist despite these conditions. Smallmouth bass abundance increased in 2025, with above average catch rates of 3.0 fish/net and 1.5 fish/net from gillnets and trap nets, respectively. Effects of smallmouth bass on the rainbow trout fishery likely occurs from competing for the same food resources such as minnows rather than preying directing on rainbow trout. Green sunfish abundance was also high during the survey with a gillnet and trap net catches of 12.5 fish/net and 13.7 fish/net, respectively. Walleye and white sucker, which were historically observed in previous surveys, were not captured in the 2015 or 2025 surveys. Anglers can expect to catch good numbers of recently stocked rainbow trout with some opportunities to catch larger fish. 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.

Leo Lake has been managed for stream trout since at least the 1930s, and has been rehabilitated with fish toxicants twice during that time (1961 and 1974). Since 2007 it has been stocked exclusively with rainbow trout. The 2015 survey was the first of two scheduled in the 2011 lake management plan to determine whether a switch to kamloop-strain yearlings, begun in 2013, would result in better attainment of management goals in the lake, particularly better long-term survival of stocked fish. Rainbow trout were abundant in Leo Lake in the fall of 2015, and fish up to 16 inches in length were present. The 2015 trap net catch was well above the upper end of the normal range (2.20 fish/set) for fall surveys of stream trout lakes in this area. Although most of the rainbow trout taken were one-year-old fish from the 2015 stocking, several older fish (up to four years old) were included in the catch, indicating good long term survival in this very accessible trout lake. Results of the 2015 survey suggest the switch to the kamloop strain may have been successful, in that more fish survived past their first year in the lake. Leo Lake supports several fish species that are generally considered incompatible with stream trout management, but none appeared excessively abundant in 2015. Walleye have been caught in fair numbers in past surveys of Leo Lake; however, none were found in 2015. Smallmouth bass were still present in Leo Lake in 2015, but only two fish were taken. White sucker, which can compete with trout for invertebrate forage, have been found in low numbers in Leo Lake in the past but were not caught in 2015. Green sunfish, which may also compete with trout, have been present in Leo Lake since at least 1981. The green sunfish trap net catch in this survey was within the normal range (0.50 - 3.27 fish/set) for stream trout lakes in this area.

The 2010 assessment of Leo Lake was done to help determine survival rates for stocked rainbow trout, and to measure progress towards the mid-range objective from the 2001 lake management plan (improving fall abundance of rainbow trout). In 2010, Clean Water Legacy funding allowed areas across the state to do some nearshore fish community sampling to improve our ability to use a fish-based Index of Biotic Integrity (IBI) to identify disturbed aquatic ecosystems. Leo Lake was selected for nearshore sampling because its accessibility allowed for use of the sampling gears required. Rainbow trout were abundant in Leo Lake in the fall of 2010. Most of the fish collected in the 2010 assessment were age-1 fish from a spring 2010 stocking of Arlee-strain yearlings. Despite the presence of walleye and smallmouth bass (both highly undesirable in a stream trout lake), survival of stocked yearlings appeared to have been good, and stocked fish seemed to have grown reasonably well. The presence of walleye in a stream trout lake is unusual in this area. The walleye gill net catch was within the normal range for a lake of this class, and the mean weight for walleye taken was above the normal range. Anglers have reported some good walleye fishing from this lake, and harvest of walleye from Leo Lake (within the legal limits) is encouraged. All walleye collected in 2010 had been produced naturally. Several year classes were represented in the catch, although none had been exceptionally strong. Walleye growth had been fast. Catches of smallmouth bass in gill nets and trap nets in 2010 were similar to catches observed in this lake in the past. Smallmouth bass may have produced a strong year class in 2010 - young-of-year fish were abundant. Sampling of the nearshore fish community was done using quarter-in-mesh trap nets, a 15-ft beach seine, backpack electrofishing gear, and quarter-inch-mesh wire minnow traps. Prior to sampling done in 2010, Leo Lake was known to support natural populations of walleye, smallmouth bass, green sunfish, white sucker, pearl dace, and bluegill. White sucker had not been sampled since 1990, and no pearl dace had been taken since 1981. Nearshore sampling in 2010 added Iowa darter to the list of fish species known to be present in this lake.

Based on Minnesota DNR survey data, anglers target Rainbow Trout, Walleye, Splake, Smallmouth Bass, and Green Sunfish in Leo. See the full species list above for catch rates, size structure, and quality scores.

Minnesota DNR records list public access for Leo. Check the DNR LakeFinder page for the launch type and directions before you go.

Leo has a maximum depth of 28 feet and a mean depth of 16.7 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Leo is from 2025.

No invasive species are on record for Leo in Minnesota DNR data. Always clean, drain, and dry your equipment to help keep it that way.