Washburn Lake
Washburn Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 14.1 ft visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 3.7 µg/L. Maximum depth: 111 ft. Surface area: 1590.19 acres.
- Clarity
- 14.1 ft
- Typical in August
- 72°F
- Max depth
- 111 ft
- Area
- 1,590 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 19
- Open water
- 226 days
Next lake in Cass County
Free interactive depth-contour map of Washburn Lake, reaching a maximum surveyed depth of 100 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Washburn Lake is a 1,590-acre mesotrophic lake in Cass County, Minnesota with a maximum depth of 111 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 21 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 103 other monitored lakes in Cass County, Washburn Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-25. Grade methodology: LakeGrade methodology.
Watch Washburn Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Good clarity, visible to about 14.1 ft. Phosphorus level: 11 µg/L. Chlorophyll-a: 3.7 µg/L. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14.1 ft | Not graded |
| Phosphorus | 11 µg/L | Good |
| Chlorophyll-a (Algae) | 3.7 µg/L | Good |
| Trophic State Index (TSI) | 40 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Washburn Lake
Compare lakeside cabins, hotels, and vacation rentals near Washburn Lake in Cass 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 Washburn Lake
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 →
Water Temperature
Washburn Lake typically sits around 72°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 76°F) and coldest in May (about 59°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 33 field readings (2011–2023) via the EPA Water Quality Portal. See the full Washburn Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Washburn Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (173,780 cells/mL) on May 9, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 111 ft |
| Surface Area | 1,590 acres |
| Shoreline Length | 19.8 mi |
| Littoral Zone | 47% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Washburn LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Washburn 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
27 surveys on file from MN DNR Fisheries. Most recent: 2025-09-24 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Spottail Shiner | 18.36 | — |
| GOS | 14.13 | — |
| Bluntnose Minnow | 14.04 | — |
| JND | 13.17 | — |
| Walleye | 9.32 | 1.12 lb |
| Bluegill | 7.58 | 0.21 lb |
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.
Walleye
Bluegill
From the 2025-09-24 survey
Walleye are currently stocked in Washburn as frylings (when available) or fingerlings in alternate (even-numbered) years. Night electrofishing was conducted on September 24th, 2025, to assess young-of-the-year (YOY) Walleye abundance. The total sample time was 2 hours, which resulted in no YOY Walleye being captured.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Washburn Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — WashburnFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Washburn (1491)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — WashburnFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — WashburnPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.083 m/yr | 6 |
| Phosphorus | → Stable | +0.2 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.09 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (54 observations).
Estimated open water season: 226 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-16 (2024) | 2008-05-06 (2008) |
| Ice-In | 2006-11-24 (2006) | 2001-12-20 (2001) |
Most recent ice-out: 2024-03-16
Reservoir Info (USACE NID)
Washburn Lake is a man-made reservoir impounded by the Washburn Lake (completed 1936), built primarily for recreation on the Daggett Brook; gravity-type dam, 7 ft tall and 39 ft long.
- Surface area
- 1,554 ac
- Normal storage
- 68,165 ac-ft
- Max storage
- 72,776 ac-ft
- Drainage area
- 43.3 sq mi
- Hazard class
- Low
- Owner
- MNDNR
Source: USACE National Inventory of Dams, NID ID MN00043 · Operator website
EPA Impairment Status
Washburn Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN11-0059-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Washburn Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Mdnr Spire Valley HatcheryRemer · 2.2 mi away · NPDES MN0069710Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #6 of 104 lakes in Cass County
Nearby Lakes in Cass County
Frequently asked questions about Washburn Lake
What is the water quality grade for Washburn Lake?
- Washburn Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 14.1 ft visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 3.7 µg/L. Maximum depth: 111 ft. Surface area: 1590.19 acres.
Is Washburn Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Washburn Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 3.7 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Washburn Lake?
- Washburn Lake typically sits around 72°F at the surface in August, from 33 EPA Water Quality Portal field readings (2011–2023). That is a typical value for the month, not a live reading.
How deep is Washburn Lake?
- Washburn Lake has a maximum depth of 111 feet. The lake covers 1590.19 acres.
What fish are in Washburn Lake?
- Fish species found in Washburn Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, burbot, greater redhorse, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, shorthead redhorse, smallmouth bass, sunfish, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Washburn Lake is located in Cass County, Minnesota.
When does Washburn Lake thaw?
- Washburn Lake typically has ice-out around Apr 19. Ice typically forms around Dec 1. The open water season is approximately 226 days.
Does Washburn Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Washburn Lake (clouds, ice, or an off-season gap). The most recent reading was high (173,780 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Washburn Lake?
- Washburn Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Washburn Lake. Public access is listed as yes.
Explore Washburn 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 Cass County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Brainerd Lakes area
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Mississippi Headwaters, ranked by water quality
Lakes in the Pine River Watersheds (Brainerd Lakes), ranked by water quality
Moderate nutrients, good water quality
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
Other Grade A Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Compare Washburn Lake With Nearby Lakes
Where this data comes from
433 measurements from 7 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
MNPCA433 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Phosphorus by Colorimetry
Monitoring station identifiers (7)
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
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
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