Prairie Lake
Prairie Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.4 ft visibility.
- Clarity
- 4.4 ft
- Typical in August
- 73°F
- Mean depth
- ~16 ft est.
- Trend
- ↓ Declining
- Public access
- Yes
Next lake in Itasca County
Why Prairie 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 Prairie 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.
Prairie Lake is a lake in Itasca County, Minnesota with an estimated average depth of about 16 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-09. Grade methodology: LakeGrade methodology.
Watch Prairie Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Prairie Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 4.4 ft. Trophic State Index: 56.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.4 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 56 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Prairie Lake
Compare lakeside cabins, hotels, and vacation rentals near Prairie Lake in Itasca 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 Prairie 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
Prairie Lake typically sits around 73°F at the surface in August. Summer average is about 71°F. Usually warmest in Jul (about 73°F) and coldest in May (about 57°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 94 field readings (2016–2025) via the EPA Water Quality Portal. See the full Prairie Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Prairie Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (143,219 cells/mL) on September 20, 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 |
|---|---|
| Average Depth | ~16 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Prairie Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Prairie Lake (West)Public
- Lower Prairie LakePublic
Fishing Prairie Lake
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Prairie Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Aquatic Plant Report — Prairie (main bay) (0594)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — Prairie (main bay)Public Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.145 m/yr | 6 |
EPA Impairment Status
Prairie 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 MN31-0384-02 · Official waterbody report · Matched by proximity (1.02 km)
Graded lakes near Prairie Lake
Prairie Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Itasca County
Frequently asked questions about Prairie Lake
What is the water quality grade for Prairie Lake?
- Prairie Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.4 ft visibility.
Is Prairie Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Prairie Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
What is the water temperature of Prairie Lake?
- Prairie Lake typically sits around 73°F at the surface in August, from 94 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.
How deep is Prairie Lake?
- No published bathymetric survey covers Prairie Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 16 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Does Prairie Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Prairie Lake (clouds, ice, or an off-season gap). The most recent reading was high (143,219 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Prairie Lake?
- Prairie Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Prairie Lake (West), Lower Prairie Lake. Public access is listed as yes.
Explore Prairie Lake across LakeGrade
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Itasca County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Mississippi Headwaters, ranked by water quality
Lakes in the Rainy Lake Watershed, ranked by water quality
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Prairie Lake
Other Lakes in Minnesota
Eutrophic Lakes in Minnesota
Where this data comes from
127 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
MNPCA127 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
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