Rainy Lake
Koochiching County, Minnesota210,200 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Rainy Lake. Here is what has been measured.
- Impaired · Mercury
- 2 aquatic invasives
- 161 ft max depth
- Public access
- Limited data
Rainy Lake in Koochiching County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 7.5 ft visibility. Maximum depth: 161 ft. Surface area: 210200.2 acres.
Minnesota DNR's Standard Survey on July 1, 2025 caught 7.17 walleye per gill net at Rainy Lake. Length samples in the latest survey that recorded them ran 1–27 inches. DNR survey details →
Free interactive depth-contour map of Rainy Lake, reaching a maximum surveyed depth of 15 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Rainy Lake is a 210,200-acre lake in Koochiching County, Minnesota with a maximum depth of 161 feet (32-foot average). The lake supports 17 documented fish species including black bullhead, black crappie, and burbot. Public access is available with 12 public boat landings.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-07-20. Methodology: how these readings are compared.
At about 210,000 acres, Rainy Lake is large enough that where you stay decides which shore you see most of. It has 12 public boat landings, so a lakefront rental is not the only way to get a boat on the water. The median ice-out date is May 4, which is when the open-water season begins. Vrbo is where to look for cabins and lake homes around Rainy Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Rainy Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch12 documented ramps
- Fishing17 species recorded
- Ice seasonIce-out around May 4
- Deep water161 ft surveyed max depth
- Big water210,200 acres
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Rainy Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Rainy 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 Rainy Lake
These are the measurements Minnesota PCA publishes for Rainy 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 7.5 ft. TSI 48.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7.5ft | 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. | 48 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Rainy Lake
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Standard Survey on July 1, 2025 caught 7.17 walleye per gill net at Rainy Lake. Length samples in the latest survey that recorded them ran 1–27 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Rainy Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
39 surveys on file from MN DNR Fisheries. Most recent: 2025-07-01 (Standard Survey).
39 surveys on file · most recent 2025-07-01 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Walleye | 11.85 | 1–27 in 2025-07-01 | 1.84 lb |
| Smallmouth Bass | 6.70 | 1–17 in 2025-07-01 | 1.18 lb |
| Black Bullhead | 5.41 | 4–12 in 2025-07-01 | 0.3 lb |
| Yellow Perch | 5.05 | 1–11 in 2025-07-01 | 0.24 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.
Walleye
Smallmouth Bass
Black Bullhead
Yellow Perch
From the 2025-07-01 survey
Rainy Lake is part of the statewide Large Lake Program, an intensive fisheries management program on the 10 largest Walleye lakes in Minnesota. The Large Lake Program includes annual standard fish assessments, annual water quality monitoring, and regularly scheduled creel surveys. A variety of sampling gear is used…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Rainy Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — RainyFisheries Lake Survey · MN DNR LakeFinder
- —Public Water Access Sites — RainyPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
161 ft
Average depth
32 ft
Surface area
210,200 acres
Shoreline
2176.3 mi
Littoral zone
9%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Recreation & Access
- Tilson BayPublic
- Black Bay Narrows - Rainy Lake Visitor CenterPublic
- Dove IslandPublic
- Sha-sha ResortPublic
- Spring LodgePublic
- Frank Bohman MemorialPublic
Showing 6 of 12 documented landings from the USGS National Boat Ramps inventory.
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Rainy Lake
Compare lakeside cabins, hotels, and vacation rentals near Rainy Lake in Koochiching 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 Rainy 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 trip? Cabins and lodging at Rainy Lake → · more Minnesota lake trips
Follow Rainy Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Rainy 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.
Ice season
Typical ice-out
May 4
Earliest Apr 6, 2012 · Latest May 22, 1950
Most recent ice-out
Apr 21
2024
107 observations · Minnesota PCA ice records
EPA Impairment Status
Rainy Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
Source: EPA ATTAINS assessment unit MN69-0694-00 · Official waterbody report
Nearby Lakes in Koochiching County
Frequently asked questions about Rainy Lake
Where is Rainy Lake?
- Rainy Lake is a lake in Koochiching County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Rainy Lake?
- Rainy Lake in Koochiching County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 7.5 ft visibility. Maximum depth: 161 ft. Surface area: 210200.2 acres.
Is Rainy Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Rainy Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
How deep is Rainy Lake?
- Rainy Lake has a maximum depth of 161 feet and an average depth of 32 feet. The lake covers 210200.2 acres.
What fish are in Rainy Lake?
- Fish species found in Rainy Lake include black bullhead, black crappie, burbot, cisco species, lake whitefish, largemouth bass, longnose sucker, northern pike, pumpkinseed, rainbow smelt, redhorse, rock bass, sauger, smallmouth bass, walleye, white sucker, yellow perch. Rainy Lake is located in Koochiching County, Minnesota.
What did the DNR fisheries survey find at Rainy Lake?
- Minnesota DNR's Standard Survey on July 1, 2025 caught 7.17 walleye per gill net at Rainy Lake. Length samples in the latest survey that recorded them ran 1–27 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Rainy Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
When does Rainy Lake thaw?
- Rainy Lake typically has ice-out around May 4.
Are there boat ramps on Rainy Lake?
- Rainy Lake has 12 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Tilson Bay, Black Bay Narrows - Rainy Lake Visitor Center, Dove Island, Sha-sha Resort, among others. Public access is listed as yes.
Can I fish at Rainy Lake?
- Rainy Lake has 12 documented boat landings 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 Rainy Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Koochiching County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Rainy Lake Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
Other Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
43 measurements from 8 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
MNPCA35 samples · 2020–2025 - USGS Minnesota Water Science Center
USGS-MN8 samples · 2023
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (8)
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 details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate