Outlet of Onamia Lake on the Rum River
Mille Lacs County, Minnesota1,044 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Outlet of Onamia Lake on the Rum River. Here is what has been measured.
- Oligotrophic
- zebra mussel
- 10 ft max depth
- Public access
- Limited data
Outlet of Onamia Lake on the Rum River in Mille Lacs County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Phosphorus: 21.8 µg/L. Chlorophyll-a (algae): 0.6 µg/L. Maximum depth: 10 ft. Surface area: 1043.71 acres.
Minnesota DNR's Standard Survey on June 13, 1989 caught 0.67 walleye per gill net at Outlet of Onamia Lake on the Rum River. DNR survey details →
Outlet of Onamia Lake on the Rum River is a 1,044-acre cold, clear oligotrophic lake in Mille Lacs County, Minnesota with a maximum depth of 10 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 8 other monitored lakes in Mille Lacs County, Outlet of Onamia Lake on the Rum River ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-08. Methodology: how these readings are compared.
What Outlet of Onamia Lake on the Rum River is good for
From access and monitoring records, not editorial picks.
- Ice seasonIce-out around Apr 4
- Big water1,044 acres
Swimming conditions
Readings onlyLimited data
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. Check local advisories before you swim.
Whether Outlet of Onamia Lake on the Rum River 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 Outlet of Onamia Lake on the Rum River
These are the measurements Minnesota PCA publishes for Outlet of Onamia Lake on the Rum River, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 21.8 µg/L. Chlorophyll-a 0.6 µg/L. TSI 37.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 21.8µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 0.6µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 37 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Outlet of Onamia Lake on the Rum River
Answers come straight from the public measurements and survey records on this page.
Minnesota DNR's Standard Survey on June 13, 1989 caught 0.67 walleye per gill net at Outlet of Onamia Lake on the Rum River.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Outlet of Onamia Lake on the Rum River’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
2 surveys on file from MN DNR Fisheries. Most recent: 1989-06-13 (Standard Survey).
2 surveys on file · most recent 1989-06-13 (Standard Survey)
37 years old| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Yellow Perch | 5.41 | 0.26 lb | |
| Black Bullhead | 5.22 | 0.38 lb | |
| Yellow Bullhead | 3.88 | 0.53 lb | |
| Northern Pike | 3.58 | 0.9 lb | |
| Pumpkinseed | 2.87 | 0.1 lb | |
| White Sucker | 2.68 | 1.81 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.
From the 1989-06-13 survey
FISH POPULATION IS MOSTLY ROUGHFISH: SUCKERS, CARP BOWFIN AND BULLHEADS WHICH ARE ALL ABOVE THEIR STATE MEDIANS. NORTHERN PIKE ARE JUST ABOVE THE AVERAGE BUT ARE SMALL IN SIZE. THE WALLEYE POPULA- TION IS LOW AND YELLOW PERCH ARE AT HALF OF THE STATE AVERAGE IN NUMBER. SOME BLUEGILLS WERE CAUGHT IN THE NATURAL…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Outlet of Onamia Lake on the Rum River. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — OnamiaFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Onamia (0341)Aquatic Plant Report · MN DNR LakeFinder
Lake Details
Max depth
10 ft
Surface area
1,044 acres
Shoreline
17.8 mi
Littoral zone
100%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
452 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,230 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Outlet of Onamia Lake on the Rum River
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Fishing Outlet of Onamia Lake on the Rum River
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 readings over time
2 seasons of samples on record (2023–2024). Calling a direction takes at least 4 years of the same measurement.
Phosphorus
Improving-4.1 µg/L/yr2 years
Chlorophyll-a
Improving-0.3 µg/L/yr2 years
Ice season
Typical ice-out
Apr 4
Earliest Mar 30, 2015 · Latest Apr 20, 2019
Most recent ice-out
Apr 5
2020
4 observations · Minnesota PCA ice records
Nearby Lakes in Mille Lacs County
Frequently asked questions about Outlet of Onamia Lake on the Rum River
Where is Outlet of Onamia Lake on the Rum River?
- Outlet of Onamia Lake on the Rum River is a lake in Mille Lacs County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Outlet of Onamia Lake on the Rum River?
- Outlet of Onamia Lake on the Rum River in Mille Lacs County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Phosphorus: 21.8 µg/L. Chlorophyll-a (algae): 0.6 µg/L. Maximum depth: 10 ft. Surface area: 1043.71 acres.
Is Outlet of Onamia Lake on the Rum River safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Outlet of Onamia Lake on the Rum River?
- Outlet of Onamia Lake on the Rum River has a maximum depth of 10 feet. The lake covers 1043.71 acres.
What did the DNR fisheries survey find at Outlet of Onamia Lake on the Rum River?
- Minnesota DNR's Standard Survey on June 13, 1989 caught 0.67 walleye per gill net at Outlet of Onamia Lake on the Rum River. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Outlet of Onamia Lake on the Rum River’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
When does Outlet of Onamia Lake on the Rum River thaw?
- Outlet of Onamia Lake on the Rum River typically has ice-out around Apr 4.
Can I fish at Outlet of Onamia Lake on the Rum River?
- Public access to Outlet of Onamia Lake on the Rum River 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 Outlet of Onamia Lake on the Rum River across LakeQuality
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Species activity outlook by water temperature and season
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Where this data comes from
20 measurements from 1 monitoring station, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Mille Lacs Band of Ojibwe DNR/Environment
MLBO_DNR_WQX20 samples · 2023–2024
Analytical methods
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 10200 H ~ Chlorophyll a-b-c Determination
- SM 4500-PJ and NO3-F
Monitoring station identifiers (1)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate