Cass

Cass Lake is a nearly 16,000 acre lake and is the largest lake in the Cass Lake chain, which altogether includes over 25,000 acres of connected waters. The lake has a mix of expansive, shallow flats and deeper water with lots of underwater structure. Walleye, Yellow Perch, and Muskellunge are the most sought-after species. While the Walleye population of Cass Lake is down a bit, there are fish distributed among numerous size and age classes. The 2025 gill net catch rate was 7.8 fish per net, less than the long-term median catch rate (12.9 fish/net). Captured fish ranged from ages 1 to 15 with most fish ages 4 to 7. Nearly half of the catch was between 17 and 20 inches. Most fish on the smaller end of that range belong to the 2021 year class and the larger fish belong to the strong 2018 year class. These fish will continue to provide the bulk of the angler catch for the next few years. The record-strong 2013 year class is still present in the population and providing anglers with quality-sized fish in the mid to upper 20-inch range. The clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, Walleye anglers should focus their effort around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was poor. Cass Lake has a history of producing strong year classes every two or three years and while we haven't seen on since 2021, the abundance of mature females is well above average and we are experimenting with a new stocking strategy to improve fry survival. The modest year classes between the strong ones help provide anglers with a wide size range of fish and reduces fishing mortality on the stronger ones. The gill net catch rate for Yellow Perch (47 per net) was similar to the long-term median (46 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population. The catch rate for fish over 9 inches in 2025 (16.5 fish/net) is the highest since annual monitoring began in 1983. The largest fish are around 13 inches in length and anglers continue to put together some impressive catches. The Northern Pike catch rate of 2.6 fish per net was similar to the long-term median of 3.0 fish per gill net. Average to below average gill net catch rates for Northern Pike over the past few years is encouraging as modest densities tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit and no more than two fish can be over 26 inches. About one-third of Northern Pike in the gill net assessment were below the protected slot limit, one-third within the size restriction, and one-third of fish were larger than 26 inches. This gives anglers a nice opportunity to put together a meal of pike comprised of fish both above and below the protected slot limit. All species in Cass Lake are managed under statewide regulations, except sunfish, for which a chain-wide five fish daily bag limit was implemented on March 1, 2021. The possession limit for sunfish remains at 20 fish. Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season. The Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members. A U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.

Temperature and dissolved oxygen measurements were collected from the deepest basin in Cass Lake, which is located wholly within the Leech Lake Reservation, on August 7th, 2025, to evaluate the quantity and quality of cold, oxygenated water (oxythermal habitat) available to Lake Whitefish, the most sensitive coldwater species present in this lake (Cisco, also known as 'Tullibee', are also present). The Leech Lake Band of Ojibwe (LLBO) holds Clean Water Act jurisdiction over waters within the exterior boundaries of the Leech Lake Reservation, which allows LLBO to establish water quality standards to protect Reservation waters and culturally important aquatic resources. During the summer, Lake Whitefish require a layer of oxythermal habitat that contains water temperatures below 17.2 degrees C (63.0 degrees F) and dissolved oxygen concentrations above 3.0 mg/L. Based on the profile from the deepest basin (maximum sampled depth 114.8 feet), the water temperature decreased below 17.2 degrees C (63.0 degrees F) at 37.9 feet and the dissolved oxygen concentration decreased to 3.0 mg/L at 79.8 feet at the time of sampling. The thickness of this layer of water in the water column was 41.9 feet, indicating that oxythermal habitat was present for Lake Whitefish. Further, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was 9.0 degrees C (48.2 degrees F). TDO3 values cooler than 17.2 degrees C (63.0 degrees F) indicate that oxythermal conditions were suitable for Lake Whitefish at the time of the survey. Data collected by the Minnesota Department of Natural Resources during the late summer period of maximum oxythermal stress (July 26th to August 24th) in 2024 the thickness of the layer of water in the water column was 29.2 feet, indicating that oxythermal habitat was present for Lake Whitefish. When inadequate oxythermal habitat is available, Lake Whitefish and Cisco are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.

Cass Lake is a nearly 16,000 acre lake and is the largest lake in the Cass Lake chain, which altogether includes over 25,000 acres of connected waters. The lake has a mix of expansive, shallow flats and deeper water with lots of underwater structure. Walleye, Yellow Perch, and Muskellunge are the most sought-after species. The Walleye population of Cass Lake is comprised of good numbers of fish distributed among numerous size and age classes. The 2024 gill net catch rate was 8.0 fish per net, less than the long-term median catch rate (13.1 fish/net). Captured fish ranged from ages 1 to 11 with most fish ages 3 to 6. Nearly 75% of the catch was between 14 and 20 inches. Most fish on the smaller end of that range belong to the 2021 year class and the larger fish belong to the strong 2018 year class. These fish will provide the bulk of the angler catch for the next few years. The record-strong 2013 year class is still present in the population and providing anglers with quality-sized fish in the mid to upper 20-inch range. The clearer-than-usual water is due to the well-established zebra mussel population and this trend is expected to continue. As a result, Walleye anglers should focus their effort around low light periods or when there is a chop on the water as the clear water tends to keep fish deeper during the day. The catch rate for age-0 Walleye (approximately 6 inches) during fall electrofishing was poor. Cass Lake has a history of producing strong year classes every two or three years and this trend is expected to continue. The modest year classes between the strong ones help provide anglers with a wide size range of fish and reduces fishing mortality on the stronger ones. The gill net catch rate for Yellow Perch (51 per net) was similar to the long-term median (45 per net). Growth rates have increased remarkably which has increased the number of keeper-sized fish in the population compared to recent years. The catch rate for fish over 9 inches in 2023 (14.2 fish/net) is among the highest since annual monitoring began in 1983. The largest fish are around 13 inches in length and anglers continue put together some impressive catches. The Northern Pike catch rate of 3.6 fish per net was similar to the long-term median of 3.0 fish per gill net. Average to below average gill net catch rates for Northern Pike over the past few years is encouraging as modest densities tend to result in faster growth rates and larger fish. Remember, Cass Lake lies in the North Central Zone for Northern Pike so the angling daily bag limit is 10 fish per day with a 22- to 26-inch protected slot limit and no more than two fish can be over 26 inches. About one-third of Northern Pike in the gill net assessment were below the protected slot limit, one-third within the size restriction, and one-third of fish were larger than 26 inches. This gives anglers a nice opportunity to put together a meal of pike comprised of fish both above and below the protected slot limit. All species in Cass Lake are managed under statewide regulations, except sunfish, for which a chain-wide five fish daily bag limit was implemented on March 1, 2021. The possession limit for sunfish remains at 20 fish. Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. The U.S. Forest Service modified the dam during winter 2015-2016 to a fixed-crest rock-arch structure with a gated bypass channel that will increase outlet capacity during high water events and aid in lowering water levels during winter to increase water storage capacity for the spring season. The Leech Lake Band of Chippewa Indians operates a commercial fishery for Lake Whitefish and Cisco on the Cass Lake chain. A limited subsistence fishery for game species is also allowed for Band members. A U.S. Environmental Protection Agency (EPA) Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. The EPA has placed a consumption advisory on Lake Whitefish from Cass Lake and Pike Bay due to elevated body burdens of dioxins in this species.

Based on Minnesota DNR survey data, anglers target Yellow Perch, Walleye, Muskellunge, Rock Bass, and Northern Pike in Cass. See the full species list above for catch rates, size structure, and quality scores.

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

Cass has a maximum depth of 120 feet, per Minnesota DNR data.

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

Yes — Cass has confirmed starry stonewort and zebra mussel. Clean, drain, and dry your equipment to avoid spreading invasives to other waters.