Maple Lake
Maple Lake in Douglas County, Minnesota has a water quality grade of A (Excellent). Water clarity: 14.1 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 3.1 µg/L. Maximum depth: 78 ft. Surface area: 830.87 acres.
- Clarity
- 14.1 ft
- Typical in August
- 73°F
- Max depth
- 78 ft
- Area
- 831 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 19
- Open water
- 228 days
Next lake in Douglas County
Free interactive depth-contour map of Maple Lake, reaching a maximum surveyed depth of 70 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Maple Lake is a 831-acre mesotrophic lake in Douglas County, Minnesota with a maximum depth of 78 feet (16-foot average). Water quality is graded A based on 2 sampling years through 2025. Overall water quality 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 2 public boat landings. Compared to the 36 other monitored lakes in Douglas County, Maple Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. 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 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: 15 µg/L. Chlorophyll-a: 3.1 µg/L. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14.1 ft | Not graded |
| Phosphorus | 15 µg/L | Good |
| Chlorophyll-a (Algae) | 3.1 µg/L | Good |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Maple Lake
Compare lakeside cabins, hotels, and vacation rentals near Maple Lake in Douglas 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.
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Water Temperature
Maple Lake typically sits around 73°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 75°F) and coldest in May (about 58°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 46 field readings (2011–2025) via the EPA Water Quality Portal. See the full Maple Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Maple Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (77,983 cells/mL) on November 16, 2025.
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 | 78 ft |
| Average Depth | 16.1 ft |
| Surface Area | 831 acres |
| Shoreline Length | 9.1 mi |
| Littoral Zone | 49% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Maple Lake (North)Public
- Maple Lake (East)Public
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Maple 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
15 surveys on file from MN DNR Fisheries. Most recent: 2025-08-04 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| MMS | 146.36 | — |
| Largemouth Bass | 20.10 | 0.75 lb |
| Bluegill | 17.64 | 0.17 lb |
| Green Sunfish | 10.61 | 0.17 lb |
| Northern Pike | 7.32 | 1.59 lb |
| Black Bullhead | 6.06 | 0.8 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.
Largemouth Bass
Bluegill
Green Sunfish
Northern Pike
From the 2025-08-04 survey
A summer trap net survey was conducted in Maple Lake by Lake Biological Monitoring and Assessment program staff beginning on August 4, 2025. Twelve trap nets were set along the shoreline in locations that encompassed multiple habitat types. Trap net sampling captured 12 species of fish, including two species that are…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Maple Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MapleFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Maple (0935)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — MapleFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MaplePublic 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 | ↑ Improving | +0.292 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.74 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.2 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (24 observations).
Estimated open water season: 228 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2016-03-24 (2016) | 2022-05-26 (2022) |
| Ice-In | 2007-11-24 (2007) | 2001-12-16 (2001) |
Most recent ice-out: 2022-05-26
EPA Impairment Status
Maple 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 MN21-0079-00 · Official waterbody report
County Ranking
Ranked #3 of 37 lakes in Douglas County
Nearby Lakes in Douglas County
Frequently asked questions about Maple Lake
What is the water quality grade for Maple Lake?
- Maple Lake in Douglas County, Minnesota has a water quality grade of A (Excellent). Water clarity: 14.1 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 3.1 µg/L. Maximum depth: 78 ft. Surface area: 830.87 acres.
Is Maple Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Maple Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 3.1 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Maple Lake?
- Maple Lake typically sits around 73°F at the surface in August, from 46 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Maple Lake?
- Maple Lake has a maximum depth of 78 feet and an average depth of 16.1 feet. The lake covers 830.87 acres.
What fish are in Maple Lake?
- Fish species found in Maple Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Maple Lake is located in Douglas County, Minnesota.
When does Maple Lake thaw?
- Maple Lake typically has ice-out around Apr 19. Ice typically forms around Dec 3. The open water season is approximately 228 days.
Does Maple Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Maple Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (77,983 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Maple Lake?
- Maple Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Maple Lake (North), Maple Lake (East). Public access is listed as yes.
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Where this data comes from
140 measurements from 2 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
MNPCA140 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
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
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