First Lake
Iron County, Michigan185 acresView mapDirections
Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.
- Impaired · Mercury
- Limited data
First Lake in Iron County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 21 ft visibility. Surface area: 184.7 acres.
- Clarity
- 21 ft
- Area
- 185 acres
- Trend
- ↑ Improving
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Watch First Lake’s letter
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Why First Lake has no grade
First Lake has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, First Lake is Not Rated — not an F. Its 21-foot median from 70 readings collected 2016–2022 is still shown as clarity, but clarity alone cannot earn a letter.
Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.
Sampling is run by EGLE and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
First Lake is a 185-acre lake in Iron County, Michigan. Overall water quality is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2022-08-26. Grade methodology: LakeQuality methodology.
What First Lake is good for
From access and monitoring records, not editorial picks.
- Clear water21 ft of visibility
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. First Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Water quality measurements for First Lake
These readings exist but are not enough for an A–F grade — see why.
Crystal clear, you can see 21 ft down. TSI 33.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 21 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 33 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 185 acres |
No bathymetric survey has been published for First Lake, so its depth is not documented here.
Fishing First Lake
Water Quality Trend: ↑ Improving
Based on 8 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.757 m/yr | 8 |
| Phosphorus | ↑ Improving | -2.46 µg/L/yr | 7 |
EPA Impairment Status
First 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 MI040301060407-03 · Official waterbody report · Matched by proximity (0.15 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of First Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Crystal Falls WfpCrystal Falls · 4.3 mi away · NPDES MIG640214Recent 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.
Graded lakes near First Lake
First Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Iron County
Frequently asked questions about First Lake
Where is First Lake?
- First Lake is a lake in Iron County, Michigan. LakeQuality has not rated this lake (UNRATED) — 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.
What is the water quality grade for First Lake?
- First Lake in Iron County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 21 ft visibility. Surface area: 184.7 acres.
Is First Lake safe to swim in?
- The letter is not a swimming clearance. First Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
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Where this data comes from
70 measurements from 1 monitoring station, 2016–2022. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- North American Lake Management Society
NALMS70 samples · 2016–2022
Monitoring station identifiers (1)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)