Mahnomen, Alstead & Arco Lake

Crow Wing County, Minnesota · MN DNR bathymetric survey

500ft Max
depth

252 acres 18 contours Public access

Paddling Index71Goodsheltered geometry · wooded shoreline · carry-in access

Get directions

Depth scale

052080180300420500

The lake

Survey readout

Mahnomen, Alstead & Arco Lake is mapped to a depth of 500 ft on the Minnesota DNR survey and covers about 252 acres in Crow Wing County, Minnesota.

Measured from the Minnesota DNR lake bathymetric contour survey.

Deepest mapped contour: 500 ft
Surface area: 252 acres
Shoreline: 6.9 mi · irregular
Aquatic vegetation: 1% of surface · NDVI estimate
Public access: Trailer Launch · Alstead Mine Lake Public Water Access Site · Minnesota DNR site · 1 more

Additional depth details18 contours

Contour depths: 0–500 ft
Recorded point soundings: 500 ft

Compare with another lake

Location

Crow Wing County, Minnesota · 15 nearest of 112 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: 46.48747, -93.98253
MN DNR lake ID: 18044000
Vertical exaggeration: 1.4×
Basemap: USDA NAIP · public domain
Model size: 2.4 MB

Paddling

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

71 / 100GoodData confidence: High

Mahnomen, Alstead & Arco 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	23.2 of 35	68% natural land cover within 150 m of shore (65% forest, 2% wetland; 6% developed)
Geometric wind exposure	Very Good	22.8 of 29	mean fetch 721 m · 18% 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	Excellent	17.6 of 18	2 DNR public access sites · carry-in or canoe launch · boat ramp
Road isolation	Good	7.5 of 18	some nearby classified roads · 7 MnDOT-classified segments within 1.2 km, peak 6,156 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 1% 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: Moderate — 65% forest and 2% 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 2019–2025). Conditions change quickly — check current weather and local conditions before going out.

Fish you might catch

from DNR surveys

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

White Sucker

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

174Fish sampled

16Species

Gamefish Rainbow Trout 55 · Largemouth Bass 16 · Northern Pike 12 · Smallmouth Bass 3

Panfish Rock Bass 28 · Bluegill 20 · Yellow Perch 19

All survey species16 species

Gamefish

Rainbow Trout55 caught · to 12″

Largemouth Bass16 caught · to 20″

Northern Pike12 caught · to 31″

Smallmouth Bass3 caught · to 19″

Walleye1 caught · to 30″

Panfish

Rock Bass28 caught · to 10″

Bluegill20 caught · to 7″

Yellow Perch19 caught · to 8″

Black Crappie4 caught · to 11″

Hybrid Sunfish4 caught · to 7″

Pumpkinseed1 caught · to 6″

Bullhead & catfish

Black Bullhead1 caught · to 10″

Yellow Bullhead1 caught · to 10″

Forage & nongame

Cisco7 caught · to 14″

Burbot1 caught · to 13″

White Sucker1 caught · to 17″

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

Infested waters listing

2 confirmed

Mussels & snails

Zebra MusselConfirmed in this water in 2017 (listed 2017).

Plants & algae

Eurasian WatermilfoilConfirmed in this water in 2009 (listed 2009).

How to identify invasive species in Minnesota lakes →

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

Mahnomen, Alstead & Arco Lake — common questions

How deep is Mahnomen, Alstead & Arco Lake?

The deepest contour on the Minnesota DNR bathymetric survey of Mahnomen, Alstead & Arco Lake is 500 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 Mahnomen, Alstead & Arco Lake?

Mahnomen, Alstead & Arco Lake covers about 252 acres in Crow Wing County, Minnesota.

What fish are in Mahnomen, Alstead & Arco Lake?

Species with survey, catch or recent-stocking evidence include burbot, largemouth bass, northern pike, rainbow trout, smallmouth bass, walleye. The page lists all 16 species and the evidence behind each.

Is there public access to Mahnomen, Alstead & Arco Lake?

Yes. The Minnesota DNR lists 2 public access sites on Mahnomen, Alstead & Arco Lake: Alstead Mine Lake Public Water Access Site (boat ramp); Mahnomen Lake Public Water Access Site (carry-in launch).

More lakes in Crow Wing County