Three Island Lake

Cass County, Minnesota · MN DNR bathymetric survey

10ft Max
depth

288 acres 2 contours Public access

Paddling Index82Very Goodwooded shoreline · away from major roads · sheltered geometry

Get directions

Depth scale

0510

The lake

Survey readout

Three Island Lake is mapped to a depth of 10 ft on the Minnesota DNR survey and covers about 288 acres in Cass County, Minnesota. Depths come from the Minnesota DNR survey of 1963.

Measured from the Minnesota DNR lake bathymetric contour survey.

Deepest mapped contour: 10 ft
Survey year: 1963
Surface area: 288 acres
Shoreline: 7.02 mi · irregular
Aquatic vegetation: 14% of surface · NDVI estimate
Public access: Trailer Launch · Three Island Lake Public Water Access Site · Minnesota DNR site

Additional depth details2 contours

Contour depths: 0–10 ft
Recorded point soundings: 10 ft

Compare with another lake

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).

⚠ Not for navigation

Spot an error? Send a correction

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: 47.03866, -94.26938
MN DNR lake ID: 11017700
Vertical exaggeration: 3.0×
Basemap: USDA NAIP · public domain
Model size: 2.4 MB

Paddling

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

82 / 100Very GoodData confidence: High

Three Island Lake has a heavily wooded and largely undeveloped setting, generally sheltered geometry, limited nearby major-road exposure.

Why this score?5 components

Included in the index

Component	Rating	Points of weight	Measurement
Natural setting	Excellent	32.7 of 35	92% natural land cover within 150 m of shore (78% forest, 10% wetland; 1% developed)
Geometric wind exposure	Very Good	21.9 of 29	mean fetch 787 m · 23% 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	Very Good	12.3 of 18	limited nearby major-road exposure · 3 MnDOT-classified segments within 1.2 km, peak 2,310 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 14% 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 — 78% forest and 10% 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 2015–2025). Conditions change quickly — check current weather and local conditions before going out.

Fish you might catch

from DNR surveys

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

Hybrid Sunfish

About these fish → the Fish of Minnesota guide

Compiled from Minnesota DNR fishery surveys. 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 2022

521Fish sampled

7Species

Gamefish Northern Pike 130 · Largemouth Bass 16

Panfish Bluegill 225 · Hybrid Sunfish 47 · Black Crappie 45

All survey species7 species

Gamefish

Northern Pike130 caught · to 27″

Largemouth Bass16 caught · to 17″

Panfish

Bluegill225 caught · to 7″

Hybrid Sunfish47 caught · to 9″

Black Crappie45 caught · to 13″

Yellow Perch37 caught · to 9″

Pumpkinseed21 caught · to 7″

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

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

Three Island Lake — common questions

How deep is Three Island Lake?

The deepest contour on the Minnesota DNR bathymetric survey of Three Island Lake is 10 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 Three Island Lake?

Three Island Lake covers about 288 acres in Cass County, Minnesota.

What fish are in Three Island Lake?

Species with survey, catch or recent-stocking evidence include largemouth bass, northern pike, black crappie, bluegill, hybrid sunfish, pumpkinseed. The page lists all 7 species and the evidence behind each.

Is there public access to Three Island Lake?

Yes. The Minnesota DNR lists a public access site on Three Island Lake: a boat ramp. It is administered by the U.S. Forest Service. DNR directions: "5 mile northwest of Longville, off County Road 125, on north shore of Three Island Lake."