Greenwood Lake
Greenwood Lake in Cook County, Minnesota has a water quality grade of A (Excellent). Water clarity: 15.1 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2.6 µg/L. Maximum depth: 112 ft. Surface area: 2042.66 acres.
- Clarity
- 15.1 ft
- Typical in August
- 54°F
- Max depth
- 112 ft
- Area
- 2,043 acres
- Type
- Oligotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- May 8
- Open water
- 209 days
Next lake in Cook County
Free interactive depth-contour map of Greenwood Lake, reaching a maximum surveyed depth of 100 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Greenwood Lake is a 2,043-acre cold, clear oligotrophic lake in Cook County, Minnesota with a maximum depth of 112 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 10 documented fish species including brook trout, cisco species, and green sunfish. Public access is available with 1 public boat landing. Compared to the 43 other monitored lakes in Cook County, Greenwood Lake ranks #29 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-08. Grade methodology: LakeGrade methodology.
Watch Greenwood 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)
Crystal clear, you can see 15.1 ft down. Phosphorus level: 10 µg/L. Chlorophyll-a: 2.6 µg/L. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15.1 ft | Not graded |
| Phosphorus | 10 µg/L | Good |
| Chlorophyll-a (Algae) | 2.6 µg/L | Good |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Greenwood Lake
Compare lakeside cabins, hotels, and vacation rentals near Greenwood Lake in Cook 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 Greenwood 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
Greenwood Lake typically sits around 54°F at the surface in August. Summer average is about 52°F. Usually warmest in Aug (about 54°F) and coldest in May (about 44°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 1,200 field readings (2018–2025) via the EPA Water Quality Portal. See the full Greenwood Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 112 ft |
| Surface Area | 2,043 acres |
| Shoreline Length | 23.4 mi |
| Littoral Zone | 26% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Greenwood LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Greenwood 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
14 surveys on file from MN DNR Fisheries. Most recent: 2025-08-11 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| CIS | 12.22 | 0.9 lb |
| Tullibee (Cisco) | 8.99 | 0.82 lb |
| Lake Trout | 2.77 | 1.43 lb |
| White Sucker | 2.48 | 2.17 lb |
| Smallmouth Bass | 1.68 | 0.55 lb |
| Green Sunfish | 1.54 | 0.09 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.
CIS
Tullibee (Cisco)
Lake Trout
White Sucker
From the 2025-08-11 survey
A targeted survey of nearshore fish species in Greenwood Lake was conducted on August 11-14, 2025, by Lake Biological Monitoring and Assessment Program staff. Nearshore sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing, mini-fyke nets, and seining with a 50-foot or…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Greenwood Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — GreenwoodFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Greenwood (1824)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — GreenwoodPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.072 m/yr | 4 |
| Phosphorus | → Stable | -0.11 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.31 µg/L/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (25 observations).
Estimated open water season: 209 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-04-10 (2012) | 2014-05-24 (2014) |
| Ice-In | 2023-11-29 (2023) | 2024-12-05 (2024) |
Most recent ice-out: 2024-04-27
EPA Impairment Status
Greenwood 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 MN16-0077-00 · Official waterbody report
County Ranking
Ranked #29 of 44 lakes in Cook County
Nearby Lakes in Cook County
Frequently asked questions about Greenwood Lake
What is the water quality grade for Greenwood Lake?
- Greenwood Lake in Cook County, Minnesota has a water quality grade of A (Excellent). Water clarity: 15.1 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2.6 µg/L. Maximum depth: 112 ft. Surface area: 2042.66 acres.
Is Greenwood Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Greenwood Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.6 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Greenwood Lake?
- Greenwood Lake typically sits around 54°F at the surface in August, from 1,200 EPA Water Quality Portal field readings (2018–2025). That is a typical value for the month, not a live reading.
How deep is Greenwood Lake?
- Greenwood Lake has a maximum depth of 112 feet. The lake covers 2042.66 acres.
What fish are in Greenwood Lake?
- Fish species found in Greenwood Lake include brook trout, cisco species, green sunfish, lake trout, lake whitefish, northern pike, smallmouth bass, tullibee (cisco), white sucker, yellow perch. Greenwood Lake is located in Cook County, Minnesota.
When does Greenwood Lake thaw?
- Greenwood Lake typically has ice-out around May 8. Ice typically forms around Dec 3. The open water season is approximately 209 days.
Are there boat ramps on Greenwood Lake?
- Greenwood Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Greenwood Lake. Public access is listed as yes.
Explore Greenwood 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 Cook County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Lake Superior Basin (MN+WI), ranked by water quality
Low nutrients, clear water, excellent for swimming
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Greenwood Lake
Other Grade A Lakes in Minnesota
Oligotrophic Lakes in Minnesota
Compare Greenwood Lake With Nearby Lakes
Where this data comes from
81 measurements from 1 monitoring station, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA81 samples · 2021–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
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