Minnesota · Cass County
Rock Lake Fishing guide
Rock Lake sits in Cass County, Minnesota, and covers 261 acres, reaching 17 ft at its deepest point. Secchi readings average around 7 ft of visibility. The Minnesota DNR has surveyed the lake 3 times, most recently in 2025, with walleye, largemouth bass, northern pike and bluegill in the nets.
DNR survey data
Fish species
No recent survey rating.
Northern pikeOne of the best around16.5per gill net19"Typical29"Biggest
Lengths measured · 37 fish
BluegillLast stocked 2023Just a few9.8per trap net4"Typical6"Biggest
Lengths measured · 47 fish
CrappieLast stocked 2023Just a few2.3per trap net5"Typical9"Biggest
Lengths measured · 44 fish
Yellow perchExcellent numbers22.5per gill net7"Typical10"Biggest
Lengths measured · 46 fish
No recent survey rating.
Rates 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 Rock Lake through the year
Northern pike
- Spring
- Pike are in the shallow bays and along new weed growth.
- Early summer
- Pike are on the outside weed edge and points.
- Summer
- Pike are on the deep weed edge and points near the coolest water they can find. With 90% of this lake 15 ft or shallower, the weed edge is the main event.
- Fall
- Pike are on the last green weeds and the breaks beside them, feeding heavily as the water drops. A 17-ft bowl cools fast, so the fall window comes early here.
Largemouth bass
- Spring
- Largemouth are moving up into the warming bays and flats, staging around wood, docks and new weeds to spawn.
- 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. With 90% of this lake 15 ft or shallower, the weed edge is the main event.
- Fall
- Largemouth are chasing bait back onto the flats and into the remaining green weeds, feeding hard and shallow before the freeze. A 17-ft bowl cools fast, so the fall window comes early here.
Season patterns for each species. Open the live map for today's wind, light and water temp.
Suggested tackle
What to bring
Top presentations for this lake's structure and clarity:
Northern pike · Hardbaits
Weedless Spoon + Trailer (Silver Minnow)
3/8–1/2 oz weedless spoon
Northern pike · Soft plastics
Paddletail Swimbait on Jighead
4–5" paddletail swimbait on a ball-head swimbait jighead
Largemouth bass · Hardbaits
Topwater Popper
2.5–3" concave-face popper
Largemouth bass · Hardbaits
Hollow-Body Frog
3–3.5" hollow-body frog
Walleye · Soft plastics
Curly-Tail Grub on Jig
3" curly-tail grub threaded on a round jighead
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 |
|---|---|---|
| 2023 | Black Crappie | 20 adults |
| 2023 | Bluegill Sunfish | 12 adults |
| 2023 | Largemouth Bass | 145 adults |
| 2022 | Walleye | 200,000 fry |
| 2019 | Walleye | 230,000 fry |
MN DNR · in their words
From the 2025 survey
Rock Lake is a 261 acre lake located three miles east of Casino in southern Cass County. Rock Lake has a maximum depth of 17 feet and is susceptible to partial winterkill events during severe winters with at least two partial kills happening in the past decade. The management plan calls for stocking Walleye fry (230,000) after severe winterkill events. Walleye were stocked in 2019 and 2022. No Walleye were sampled in this survey. A standard survey using gill nets and trap nets was conducted in August of 2025 to assess fish populations and provide angler information.
Northern Pike had a gill net catch of 16.5/net. Fish ranged from 17.0 to 29.0 inches with an average of 20.2 inches. Northern Pike in the protected 22-26 inch slot made up 3% of the catch with 6% at least 26 inches in length. The population is dominated by young fish with age 2 and 3 fish making up 91% of the catch. Anglers can expect lots of action on smaller fish.
Read the full DNR narrative
Anglers will find plenty of Black Crappie in Rock, but they run on the small side. Gill nets had a catch of 17.5/net with fish ranging from 4.6 to 8.2 inches with an average of 5.9 inches. Trap nets had a catch of 2.3/net with fish ranging from 5.0 to 9.6 inches with an average of 6.9 inches. For both gear types combined, 14% of the catch was at least 8 inches in length. Bluegills had a trap net catch of 9.8/net. They also ran on the small side with fish ranging from 3.0 to 6.7 inches with an average of 4.6 inches.
Anglers may want to target Yellow Perch in Rock. Fish ranged from 5.3 to 10.9 inches with an average of 7.7 inches. Yellow Perch at least 8 inches in length made up 47% of the catch.
Other species sampled included Bowfin (Dogfish), Brown Bullhead, Hybrid Sunfish, Pumpkinseed, White Sucker and Yellow Bullhead.
Narrative text from the Minnesota DNR lake survey.
Recent reports
Rock Lake fishing reports
Recent reports on Rock 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
- Rock Lake (trailer launch)
DNR bathymetry
Rock Lake depth map
Within 30 miles
Nearby lakes
- Beauty Lake · 19 ac · 1.8 mi
- Green Bass Lake · 44 ac · 2.3 mi
- Pillager Lake · 205 ac · 3.9 mi
- Agate Lake · 157 ac · 5.3 mi
- Sylvan Lake · 894 ac · 5.3 mi
- Gull Lake · 10,010 ac · 5.4 mi
- Dade Lake · 99 ac · 5.9 mi
- Margaret Lake · 251 ac · 7.2 mi
Quick answers
Frequently asked questions
How deep is Rock Lake?
Rock Lake reaches 17 ft at its deepest point; about 90% of the lake is littoral (15 ft or shallower).
How big is Rock Lake?
Rock Lake covers 261 acres with about 3.4 miles of shoreline.
How clear is the water in Rock Lake?
DNR Secchi readings on Rock Lake average 7 ft of visibility, middling clarity for a Minnesota lake.
What fish are in Rock Lake?
Minnesota DNR surveys (most recently 2025) record walleye, largemouth bass, northern pike, bluegill, crappie, yellow perch, rock bass.
Is Rock Lake stocked?
Yes. The DNR stocked black crappie, bluegill sunfish and largemouth bass in 2023; the stocking table on this page lists every year back to 2019.
Does Rock Lake have a public access?
Yes. Rock Lake has one public access site: Rock Lake (trailer launch).
How big do northern pike get in Rock Lake?
The biggest northern pike measured in recent DNR surveys taped 29".
When was Rock Lake last surveyed?
The Minnesota DNR last surveyed Rock Lake in 2025, the most recent of 3 surveys on record.
Page updated .
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