Upper Orono Lake
Sherburne County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for Upper Orono Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- 2 aquatic invasives
- Public access
- Limited data
Upper Orono Lake in Sherburne County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.5 ft visibility. Phosphorus: 130.5 µg/L. Chlorophyll-a (algae): 47.5 µg/L.
Upper Orono Lake is a productive, nutrient-rich eutrophic lake in Sherburne County, Minnesota. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 17 other monitored lakes in Sherburne County, Upper Orono Lake ranks #14 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. Methodology: how these readings are compared.
What Upper Orono Lake is good for
From access and monitoring records, not editorial picks.
- Ice seasonIce-out around Apr 3
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Upper Orono Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Upper Orono 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 Upper Orono Lake
These are the measurements Minnesota PCA publishes for Upper Orono Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 3.5 ft. Phosphorus 130.5 µg/L. Chlorophyll-a 47.5 µg/L. TSI 67.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 131µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 47.5µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 67 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Upper Orono Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Upper Orono Lake typically sits around 63°F at the surface in September. Summer average is about 72°F. Usually warmest in Jul (about 77°F) and coldest in May (about 63°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (63°F) to its warmest (77°F).
Typical surface water temperature by month, from 30 field readings (2024–2025) via the EPA Water Quality Portal. See the full Upper Orono Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Upper Orono Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (483,059 cells/mL) on October 4, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Upper Orono Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Public Water Access Sites — Upper OronoPublic Water Access Sites · MN DNR LakeFinder
Stays via Stay22
Stays near Upper Orono Lake
Compare lakeside cabins, hotels, and vacation rentals near Upper Orono Lake in Sherburne 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Upper Orono Lake are listed below.
Top-rated places to stay near Upper Orono 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 whole trip? See where to stay at Minnesota’s top lakes →
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Fishing Upper Orono 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.
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Ice season
Typical ice-out
Apr 3
Earliest Mar 27, 2017 · Latest Apr 27, 2018
Typical ice-in
Nov 29
Earliest Nov 10, 2018 · Latest Dec 19, 2015
Most recent ice-out
Mar 28
2025
10 observations · Minnesota PCA ice records
EPA Impairment Status
Upper Orono Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN71-0013-01 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Upper Orono Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Otsego Wwtp WestOtsego · 4.3 mi away · NPDES MN0066257Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Sherburne County
Frequently asked questions about Upper Orono Lake
Where is Upper Orono Lake?
- Upper Orono Lake is a lake in Sherburne County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Upper Orono Lake?
- Upper Orono Lake in Sherburne County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 3.5 ft visibility. Phosphorus: 130.5 µg/L. Chlorophyll-a (algae): 47.5 µg/L.
Is Upper Orono Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Upper Orono Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Upper Orono Lake?
- Upper Orono Lake typically sits around 63°F at the surface in September, from 30 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
When does Upper Orono Lake thaw?
- Upper Orono Lake typically has ice-out around Apr 3. Ice typically forms around Nov 29. The open water season is approximately 240 days.
Does Upper Orono Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Upper Orono Lake (clouds, ice, or an off-season gap). The most recent reading was high (483,059 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Can I fish at Upper Orono Lake?
- Public access to Upper Orono Lake is listed as yes on the lake record. 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 Upper Orono Lake across LakeQuality
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Where this data comes from
100 measurements from 3 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
MNPCA100 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 (3)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Ice data from Minnesota DNR Climate