First Black Lake
Iron County, Wisconsin23 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for First Black Lake. Here is what has been measured.
- Eutrophic
- 19 ft max depth
- Limited data
First Black Lake in Iron County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2.5 ft visibility. Phosphorus: 27.5 µg/L. Maximum depth: 19 ft. Surface area: 23 acres.
Wisconsin DNR lists Musky as present on First Black Lake. DNR survey details →
First Black Lake is a 23-acre productive, nutrient-rich eutrophic lake in Iron County, Wisconsin with a maximum depth of 19 feet. The lake supports 5 documented fish species including Musky, Panfish, and Largemouth Bass. Compared to the 15 other monitored lakes in Iron County, First Black Lake ranks #15 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-07-03. Methodology: how these readings are compared.
What First Black Lake is good for
From access and monitoring records, not editorial picks.
- Fishing5 species recorded
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 First Black Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for First Black Lake
These are the measurements Wisconsin DNR publishes for First Black Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.5 ft of visibility. Phosphorus 27.5 µg/L. TSI 58.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 27.5µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 58 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about First Black Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
First Black Lake typically sits around 65°F at the surface in September. Summer average is about 70°F. Usually warmest in Jul (about 72°F) and coldest in May (about 60°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (60°F) to its warmest (72°F).
Typical surface water temperature by month, from 31 field readings (2024–2026) via the EPA Water Quality Portal. See the full First Black Lake water temperature breakdown →
Wisconsin DNR lists Musky as present on First Black Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows First Black Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2005. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
19 ft
Surface area
23 acres
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Stays near First Black Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing First Black Lake
- → First Black Lake fishing: DNR survey catch rates, species & stocking
- → First Black Lake fishing forecast & best times (species outlook + 14-day solunar calendar)
- → First Black Lake fishing regulations (limits, seasons, special rules)
- → Is it safe to eat fish from First Black Lake? (mercury & PFAS guide)
Water Quality Trend: Stable
Based on 7 years of monitoring (2020–2026).
Water clarity
Stable7 years
Phosphorus
Stable-0.01 µg/L/yr5 years
Nearby Lakes in Iron County
Frequently asked questions about First Black Lake
Where is First Black Lake?
- First Black Lake is a lake in Iron County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of First Black Lake?
- First Black Lake in Iron County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2.5 ft visibility. Phosphorus: 27.5 µg/L. Maximum depth: 19 ft. Surface area: 23 acres.
Is First Black 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 First Black Lake?
- First Black Lake typically sits around 65°F at the surface in September, from 31 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is First Black Lake?
- First Black Lake has a maximum depth of 19 feet. The lake covers 23 acres.
What fish are in First Black Lake?
- Fish species found in First Black Lake include Musky, Panfish, Largemouth Bass, Northern Pike, Walleye. First Black Lake is located in Iron County, Wisconsin.
What did the DNR fisheries survey find at First Black Lake?
- Wisconsin DNR lists Musky as present on First Black Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows First Black Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Explore First Black Lake across LakeQuality
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Where this data comes from
86 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX86 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
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
Fish and recreation data from Wisconsin DNR Lakes