Big Maggie Lake
Iron County, MichiganView mapDirections
EGLE publishes the water-quality measurements for Big Maggie Lake. Here is what has been measured.
- Oligotrophic
Big Maggie Lake in Iron County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 11.5 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 1.4 µg/L.
Big Maggie Lake is a cold, clear oligotrophic lake in Iron County, Michigan. Overall water quality is improving over recent sampling years. Compared to the 20 other monitored lakes in Iron County, Big Maggie Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2023-08-27. Methodology: how these readings are compared.
For a place on the water, look through cabin and lake-house rentals near Big Maggie Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Big Maggie Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11.5 ft of visibility
Swimming conditions
Readings onlyLow algae
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 Big Maggie Lake is safe to swim in today is a call for the Michigan Department of Environment, Great Lakes, and Energy (EGLE) and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Big Maggie Lake
These are the measurements EGLE publishes for Big Maggie Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 11.5 ft. Phosphorus 10 µg/L. Chlorophyll-a 1.4 µg/L. TSI 38.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 11.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 10µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 1.4µg/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. | 38 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Big Maggie Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Big Maggie Lake typically sits around 67°F at the surface in August. Summer average is about 64°F. Usually warmest in Aug (about 67°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (55°F) to its warmest (67°F).
Typical surface water temperature by month, from 36 field readings (2016–2016) via the EPA Water Quality Portal. See the full Big Maggie Lake water temperature breakdown →
Stays via Stay22
Stays near Big Maggie Lake
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Top-rated places to stay near Big Maggie Lake
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Fishing Big Maggie Lake
Water Quality Trend: Improving
Based on 7 years of monitoring (2016–2023).
Water clarity
Improving5 years
Phosphorus
Improving-0.96 µg/L/yr7 years
Chlorophyll-a
Stable-0.09 µg/L/yr7 years
Nearby Lakes in Iron County
Frequently asked questions about Big Maggie Lake
Where is Big Maggie Lake?
- Big Maggie Lake is a lake in Iron County, Michigan. Its water-quality measurements are published by EGLE and shown on this page as reported.
What is the water quality of Big Maggie Lake?
- Big Maggie Lake in Iron County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 11.5 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 1.4 µg/L.
Is Big Maggie Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Big Maggie Lake?
- Big Maggie Lake typically sits around 67°F at the surface in August, from 36 EPA Water Quality Portal field readings (2016–2016). That is a typical value for the month, not a live reading.
Explore Big Maggie Lake across LakeQuality
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Where this data comes from
77 measurements from 1 monitoring station, 2016–2023. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- Michigan EGLE - MiCorps
21MICH_MICORPS77 samples · 2016–2023
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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.