Big Lake
Big Lake in Beltrami County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.7 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Maximum depth: 35 ft. Surface area: 3597.95 acres.
- Clarity
- 9.7 ft
- Max depth
- 35 ft
- Area
- 3,598 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- Apr 24
- Open water
- 217 days
Next lake in Beltrami County
Free interactive depth-contour map of Big Lake, reaching a maximum surveyed depth of 35 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Big Lake is a 3,598-acre mesotrophic lake in Beltrami County, Minnesota with a maximum depth of 35 feet (14-foot average). Water quality is graded A based on 3 sampling years through 2025. Water clarity is improving over recent sampling years. The lake supports 17 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 84 other monitored lakes in Beltrami County, Big Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-08. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature for this lake. Check your state or county health department before you swim.
Elevated cyanobacteria detected — see the algae advisory
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 9.7 ft. Phosphorus level: 15 µg/L. Chlorophyll-a: 4.8 µg/L. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.7 ft | Not graded |
| Phosphorus | 15 µg/L | Good |
| Chlorophyll-a (Algae) | 4.8 µg/L | Good |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Big Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Lake in Beltrami County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Big Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Blue-Green Algae (Cyanobacteria)
A significant bloom was detected. Avoid swimming and keep children and dogs out of the water — blue-green algae can produce toxins.
EPA CyAN satellite reading from August 7, 2026 (rising) · 16 weekly estimates shown (61 on record). Satellite estimates cover only open water and can miss shoreline scums — always check your state’s current advisory before entering. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 35 ft |
| Average Depth | 14.1 ft |
| Surface Area | 3,598 acres |
| Shoreline Length | 16.6 mi |
| Littoral Zone | 59% |
| Public Access | Yes |
Recreation & Access
- Big LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Big Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
DNR Fisheries Survey Summary
17 surveys on file from MN DNR Fisheries. Most recent: 2025-06-10 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| MMS | 92.68 | — |
| Yellow Perch | 54.54 | 0.2 lb |
| BMS | 39.63 | — |
| Bluntnose Minnow | 31.10 | — |
| Muskellunge | 24.43 | 10.42 lb |
| JND | 15.59 | — |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Yellow Perch
Muskellunge
From the 2025-06-10 survey
Big Lake is a 3,596 acre lake with a maximum depth of 35 feet located 13 miles east of Bemidji in Beltrami County. The Big Lake boat launch is located on the east shore and can be accessed from Mission Road. A total of 53 Walleye were captured in the 2025 survey, and they ranged in length from 10.5 inches to 22 inches…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Big Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BigFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Big (1734)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — BigFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BigPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.207 m/yr | 6 |
| Phosphorus | → Stable | -0.04 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +0.21 µg/L/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (24 observations).
Estimated open water season: 217 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-17 (2024) | 2008-05-12 (2008) |
| Ice-In | 2003-11-08 (2003) | 2001-12-20 (2001) |
Most recent ice-out: 2025-04-28
County Ranking
Ranked #1 of 85 lakes in Beltrami County
Nearby Lakes in Beltrami County
Frequently asked questions about Big Lake
What is the water quality grade for Big Lake?
- Big Lake in Beltrami County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.7 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Maximum depth: 35 ft. Surface area: 3597.95 acres.
Is Big Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Big Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 4.8 µg/L. Always check local health department advisories before swimming.
How deep is Big Lake?
- Big Lake has a maximum depth of 35 feet and an average depth of 14.1 feet. The lake covers 3597.95 acres.
What fish are in Big Lake?
- Fish species found in Big Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, hybrid sunfish, largemouth bass, muskellunge, northern pike, pumpkinseed, rock bass, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Big Lake is located in Beltrami County, Minnesota.
When does Big Lake thaw?
- Big Lake typically has ice-out around Apr 24. Ice typically forms around Nov 27. The open water season is approximately 217 days.
Does Big Lake have blue-green algae?
- EPA CyAN satellite data last estimated Big Lake's cyanobacteria density at 222,844 cells/mL (high bloom risk). Satellite estimates cover open water and can miss shoreline scums, so always check Minnesota's current advisory before entering.
Are there boat ramps on Big Lake?
- Big Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Big Lake. Public access is listed as yes.
Explore Big Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Beltrami County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Mississippi Headwaters, ranked by water quality
Moderate nutrients, good water quality
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Big Lake
Other Grade A Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Compare Big Lake With Nearby Lakes
Beltrami County · Grade D
Beltrami County · Grade D
Beltrami County · Grade C
Beltrami County · Grade D
Beltrami County · Grade C
Beltrami County · Grade A
Where this data comes from
218 measurements from 4 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA182 samples · 2020–2025 - Leech Lake Band of Ojibwe
LEECHLAK_WQX36 samples · 2024–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Nitrate-Nitrite Nitrogen by Colorimetry
Monitoring station identifiers (4)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate