Big Swan Lake
Todd County, Minnesota947 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Big Swan Lake. Here is what has been measured.
- Impaired · Mercury
- 45 ft max depth
- Public access
- Limited data
Big Swan Lake in Todd County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9 ft visibility. Maximum depth: 45 ft. Surface area: 946.56 acres.
Minnesota DNR's Targeted Survey on July 14, 2025 caught 0.08 walleye per trap net at Big Swan Lake. DNR survey details →
Free interactive depth-contour map of Big Swan Lake, reaching a maximum surveyed depth of 45 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Big Swan Lake is a 947-acre lake in Todd County, Minnesota with a maximum depth of 45 feet (18-foot average). Overall water quality is improving over recent sampling years. The lake supports 16 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-16. Methodology: how these readings are compared.
Big Swan Lake covers about 950 acres in Todd County. It has one public boat landing. The median ice-out date is April 13, which is when the open-water season begins. For a place on the water, look through cabin and lake-house rentals near Big Swan Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Big Swan Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing16 species recorded
- Ice seasonIce-out around Apr 13
- Deep water45 ft surveyed max depth
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Big Swan Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Big Swan Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Big Swan Lake
These are the measurements Minnesota PCA publishes for Big Swan Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 9 ft. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Big Swan Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Big Swan Lake typically sits around 54°F at the surface in October. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in Oct (about 54°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (54°F) to its warmest (75°F).
Typical surface water temperature by month, from 33 field readings (2023–2025) via the EPA Water Quality Portal. See the full Big Swan Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Big Swan Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (194,089 cells/mL) on November 22, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Minnesota DNR's Targeted Survey on July 14, 2025 caught 0.08 walleye per trap net at Big Swan Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Swan Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
20 surveys on file from MN DNR Fisheries. Most recent: 2025-07-14 (Targeted Survey).
20 surveys on file · most recent 2025-07-14 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 25.06 | 2–8 in 2025-07-14 | 0.16 lb |
| Bluntnose Minnow | 8.30 | ||
| Northern Pike | 8.24 | 13–22 in 2025-07-14 | 2.18 lb |
| Largemouth Bass | 7.83 | 7–17 in 2025-07-14 | 1.47 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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.
Bluegill
Northern Pike
Largemouth Bass
From the 2025-07-14 survey
A targeted survey of nearshore fish species in Big Swan Lake was conducted on July 14- 16, 2025, by Lake Biological Monitoring and Assessment Program (LBMA) staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Big Swan Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Big SwanFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Big Swan (1060)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — Big SwanFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Big SwanPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
45 ft
Average depth
18 ft
Surface area
947 acres
Shoreline
7.8 mi
Littoral zone
43%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
43 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,178 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Big Swan LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Big Swan Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Swan Lake in Todd 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 Swan Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Follow Big Swan Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Big Swan Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Ice season
Typical ice-out
Apr 13
Earliest Mar 22, 2012 · Latest May 11, 2013
Typical ice-in
Nov 29
Earliest Nov 2, 2020 · Latest Dec 22, 2015
Most recent ice-out
Apr 30
2022
70 observations · Minnesota PCA ice records
EPA Impairment Status
Big Swan Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN77-0023-00 · Official waterbody report
Nearby Lakes in Todd County
Frequently asked questions about Big Swan Lake
Where is Big Swan Lake?
- Big Swan Lake is a lake in Todd County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Big Swan Lake?
- Big Swan Lake in Todd County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9 ft visibility. Maximum depth: 45 ft. Surface area: 946.56 acres.
Is Big Swan Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Big Swan Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Big Swan Lake?
- Big Swan Lake typically sits around 54°F at the surface in October, from 33 EPA Water Quality Portal field readings (2023–2025). That is a typical value for the month, not a live reading.
How deep is Big Swan Lake?
- Big Swan Lake has a maximum depth of 45 feet and an average depth of 18 feet. The lake covers 946.56 acres.
What fish are in Big Swan Lake?
- Fish species found in Big Swan Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, white sucker, yellow bullhead, yellow perch. Big Swan Lake is located in Todd County, Minnesota.
What did the DNR fisheries survey find at Big Swan Lake?
- Minnesota DNR's Targeted Survey on July 14, 2025 caught 0.08 walleye per trap net at Big Swan Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Big Swan Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does Big Swan Lake thaw?
- Big Swan Lake typically has ice-out around Apr 13. Ice typically forms around Nov 29. The open water season is approximately 230 days.
Does Big Swan Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Big Swan Lake (clouds, ice, or an off-season gap). The most recent reading was high (194,089 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Big Swan Lake?
- Big Swan Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Big Swan Lake. Public access is listed as yes.
Can I fish at Big Swan Lake?
- Big Swan Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Big Swan Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
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Fish species and best lakes in Todd County
Species activity outlook by water temperature and season
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Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Sauk River Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
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Where this data comes from
211 measurements from 3 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
MNPCA211 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (3)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
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