Rainy Lake
Rainy Lake in Koochiching County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 7.5 ft visibility. Maximum depth: 161 ft. Surface area: 210200.2 acres.
- Clarity
- 7.5 ft
- Max depth
- 161 ft
- Area
- 210,200 acres
- Public access
- Yes
- Ice-out
- May 4
Next lake in Koochiching County
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.
Why Rainy Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Rainy Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
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 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-07-20. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Rainy Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Moderate clarity, visible to about 7.5 ft. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay 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
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Planning a trip? Cabins and lodging at Rainy Lake → · more Minnesota lake trips
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 161 ft |
| Average Depth | 32 ft |
| Surface Area | 210,200 acres |
| Shoreline Length | 2176.3 mi |
| Littoral Zone | 9% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Black Bay Narrows - Rainy Lake Visitor CenterPublic
- Dove IslandPublic
- Sha-sha ResortPublic
- Spring LodgePublic
- Camp Kooch-i-chingSemi-private
- Rainy Lake HouseboatsSemi-private
Fish Species
Click a species to see every graded 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.
DNR Fisheries Survey Summary
39 surveys on file from MN DNR Fisheries. Most recent: 2025-07-01 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Walleye | 11.85 | 1.84 lb |
| Smallmouth Bass | 6.70 | 1.18 lb |
| CIS | 5.85 | 0.74 lb |
| Black Bullhead | 5.41 | 0.3 lb |
| Yellow Perch | 5.05 | 0.24 lb |
| BLH | 2.79 | 0.17 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
Smallmouth Bass
CIS
Black Bullhead
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
Ice Season
Historical ice data from Minnesota DNR (107 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-04-06 (2012) | 1950-05-22 (1950) |
| Ice-In | 2024-01-04 (2024) | 2024-01-04 (2024) |
Most recent ice-out: 2024-04-21
Graded lakes near Rainy Lake
Rainy Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Koochiching County
Frequently asked questions about Rainy Lake
What is the water quality grade for Rainy Lake?
- Rainy Lake in Koochiching County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 7.5 ft visibility. Maximum depth: 161 ft. Surface area: 210200.2 acres.
Is Rainy Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Rainy Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
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.
When does Rainy Lake thaw?
- Rainy Lake typically has ice-out around May 4.
Are there boat ramps on Rainy Lake?
- Rainy Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Black Bay Narrows - Rainy Lake Visitor Center, Dove Island, Sha-sha Resort, Spring Lodge, among others. Public access is listed as yes.
Explore Rainy 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 Koochiching County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Rainy Lake Watershed, ranked by water quality
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
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)
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
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