Rock Lake

Cass County, Minnesota · MN DNR bathymetric survey

15ft Max
depth

261 acres 3 contours Public access

Paddling Index70Goodsheltered geometry · wooded shoreline

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Depth scale

051015

The lake

Survey readout

Rock Lake is mapped to a depth of 15 ft on the Minnesota DNR survey and covers about 261 acres in Cass County, Minnesota. Depths come from the Minnesota DNR survey of 1965.

Measured from the Minnesota DNR lake bathymetric contour survey.

Deepest mapped contour: 15 ft
Survey year: 1965
Surface area: 261 acres
Shoreline: 3.3 mi · lobed
Aquatic vegetation: 9% of surface · NDVI estimate
Public access: Trailer Launch · Rock Lake Public Water Access Site · Minnesota DNR site

Additional depth details3 contours

Contour depths: 0–15 ft
Recorded point soundings: 15 ft

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Location

Cass County, Minnesota · 15 nearest of 123 lakes · tap a dot for that lake

Chart data

Provenance

Sources: MN DNR Lake Bathymetric Contours, USGS 3DEP, USDA NAIP (public domain), OpenStreetMap (ODbL).

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Map details & sources4 sources

All layers registered to one bounding box; positions in WGS 84.

Survey-derived depth contours drape over USGS 3DEP elevation, with a USDA NAIP aerial basemap and OpenStreetMap shoreline. Color shows surveyed depth; dark lines are the survey's own isobaths.

Coordinates: 46.42664, -94.47678
MN DNR lake ID: 11032400
Vertical exaggeration: 3.0×
Basemap: USDA NAIP · public domain
Model size: 2.1 MB

Paddling

Paddling Index methodology v1.0 · calculated 2026-09-25

70 / 100GoodData confidence: High

Rock Lake has a mostly natural, lightly developed setting, generally sheltered geometry, some nearby classified roads.

Why this score?5 components

Included in the index

Component	Rating	Points of weight	Measurement
Natural setting	Very Good	27.2 of 35	79% natural land cover within 150 m of shore (26% forest, 52% wetland; 17% developed)
Geometric wind exposure	Very Good	18.1 of 29	mean fetch 1,013 m · 0% of sampled water within 500 m of shelter · generally short fetch
Motor & speed rules	Not modeled	—	Minnesota’s lake-by-lake motor, speed and no-wake rules are mostly county and city ordinances, not map data, so they are not part of the Minnesota index. Check local signage and ordinances before going out.
Public access	Good	15.0 of 18	1 DNR public access site · boat ramp
Road isolation	Good	9.3 of 18	some nearby classified roads · 1 MnDOT-classified segment within 1.2 km, peak 1,524 vehicles/day

Additional paddling considerations

These describe the lake but are not part of the v1 Paddling Index and do not change the number above.

Wake sensitivity: Low — wide enough that wakes disperse over most of the lake
Aquatic vegetation: Low — approximately 9% mapped coverage · NAIP aerial imagery (NDVI)
Observed motorized activity: Unknown — No lake-level measurement of boat traffic is available. Legal permission to operate motors is not evidence of use.
Wildlife habitat potential: High — 26% forest and 52% wetland cover within 150 m of shore

Compare Minnesota lakes by Paddling Index →

How this index is calculated. The Paddling Index is a relative composite derived from lake geometry and public land-cover, access and traffic-count data. It is not a user review, a safety rating, or a prediction of an individual outing. Differences of a few points should not be treated as meaningful — an 84 and an 82 are broadly comparable. Components and weights for Minnesota lakes: natural setting 35%, geometric wind exposure 29%, public access 18%, road isolation 18%. Motor, speed and no-wake rules are not modeled for Minnesota, and traffic counts cover state, county and some city roads but not township roads. Where a component has no data the remaining weights are renormalized and the confidence rating is lowered; below Medium confidence no number is shown. Minnesota scores are relative to other Minnesota lakes and are not directly comparable with Paddling Index scores on our sister sites, which use different data sources, some with a watercraft-rules component. Sources: MN DNR lake bathymetry outline, USGS/MRLC NLCD Land Cover (2021), MN DNR Water Access Sites and Fishing Piers & Shore Fishing Sites (2026-09) and MnDOT Annual Average Daily Traffic (counts 2023). Conditions change quickly — check current weather and local conditions before going out.

Fish you might catch

from DNR surveys & active stocking

12 species with recent evidence in this lake — sized relative to each other. Illustrations are AI-generated representative adults in everyday colors, not photographs (provenance).

Walleyestocked

White Sucker

Hybrid Sunfish

About these fish → the Fish of Minnesota guide

Compiled from Minnesota DNR fishery surveys and Minnesota DNR stockings within the last 10 years. Silhouettes are stylized and scaled to typical adult sizes relative to one another. Presence is not a promise — fishing isn’t a sure thing.

Fishery

surveyed 2025

383Fish sampled

11Species

Gamefish Northern Pike 37 · Bowfin 2 · Largemouth Bass 2

Panfish Pumpkinseed 71 · Bluegill 47 · Yellow Perch 46

All survey species11 species

Gamefish

Northern Pike37 caught · to 29″

Bowfin2 caught · to 16″

Largemouth Bass2 caught · to 10″

Panfish

Pumpkinseed71 caught · to 5″

Bluegill47 caught · to 6″

Yellow Perch46 caught · to 10″

Black Crappie44 caught · to 9″

Hybrid Sunfish5 caught · to 6″

Bullhead & catfish

Yellow Bullhead120 caught · to 12″

Brown Bullhead8 caught · to 13″

Forage & nongame

White Sucker1 caught · to 15″

Length is the largest fish netted in the survey, not an angler record. Source: Minnesota DNR lake survey (LakeFinder).

DNR stocking

state stocking record · 2019–2023

Fish the Minnesota DNR has planted in this lake — what was added, distinct from what a survey netted above.

Largemouth Bass145 stocked · 2023

Black Crappie20 stocked · 2023

Bluegill Sunfish12 stocked · 2023

Walleye430,000 stocked · 2019–2022 · 2 plantings

Source: Minnesota DNR LakeFinder stocking report. LakeFinder lists the last 10 years of stocking only.

Infested waters listing

Not on the Minnesota DNR’s infested waters list as of September 9, 2026. This does not mean the lake is free of invasive species: the list covers certain species only, and a species can be present before anyone finds it.

What does the infested waters list mean?

The Minnesota DNR lists a lake, river, pond or wetland as infested when it contains an aquatic invasive species that could spread to other waters, or when it is connected to a water where one is present. Activities such as bait harvest and water use are managed differently on infested waters. Check the current list before moving water, bait or equipment.

Source: Minnesota Department of Natural Resources. List of Infested Waters, September 9, 2026. https://www.dnr.state.mn.us/invasives/ais/infested.html

Quick answers

Rock Lake — common questions

How deep is Rock Lake?

The deepest contour on the Minnesota DNR bathymetric survey of Rock Lake is 15 ft. That is the deepest depth the historical survey map records, which may differ from the deepest point of the lake itself.

How big is Rock Lake?

Rock Lake covers about 261 acres in Cass County, Minnesota.

What fish are in Rock Lake?

Species with survey, catch or recent-stocking evidence include largemouth bass, northern pike, walleye, black crappie, bluegill, bowfin. The page lists all 12 species and the evidence behind each.

Is there public access to Rock Lake?

Yes. The Minnesota DNR lists a public access site on Rock Lake: a boat ramp with a boat dock and restrooms. It is administered by the DNR Division of Forestry. DNR directions: "6 miles North of Pillager on Cass Co. Rd. #1, then 1 mile West on Forestry Campground Road."