Round Lake
Lenawee County, Michigan507 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Oligotrophic
- Impaired · Mercury
- #2 of 5 in the county
- 67 ft max depth
Round Lake in Lenawee County, Michigan has a water quality grade of A (Excellent). Water clarity: 12.3 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 2 µg/L. Maximum depth: 67 ft. Surface area: 507.3 acres.
- Clarity
- 12.3 ft
- Typical in September
- 60°F
- Max depth
- 67 ft
- Area
- 507 acres
- Type
- Oligotrophic
- Phosphorus
- 8 µg/L
- Chlorophyll-a
- 2 µg/L
- Trend
- ↓ Declining
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Round Lake is a 507-acre cold, clear oligotrophic lake in Lenawee County, Michigan with a maximum depth of 67 feet. Water quality is graded A based on 2 sampling years through 2023. Overall water quality is declining over recent sampling years. The lake supports 25 documented fish species including Blackchin shiner, Blacknose shiner, and Bluegill. Compared to the 4 other monitored lakes in Lenawee County, Round Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2023-09-18. Grade methodology: LakeQuality methodology.
What Round Lake is good for
From access and monitoring records, not editorial picks.
- Clear water12.3 ft of visibility
- Fishing25 species recorded
- Deep water67 ft surveyed max depth
Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The A is nutrients and algae, not a swimming clearance. Round Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Good clarity, visible to about 12.3 ft. Phosphorus 8 µg/L. Chlorophyll-a 2 µg/L. TSI 38. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12.3 ft | Not graded |
| Phosphorus | 8 µg/L | Good |
| Chlorophyll-a (Algae) | 2 µg/L | Good |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Water Temperature
Round Lake typically sits around 60°F at the surface in September. Summer average is about 61°F. Usually warmest in Jul (about 62°F) and coldest in Mar (about 42°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 1,397 field readings (2010–2023) via the EPA Water Quality Portal. See the full Round Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 67 ft |
| Surface Area | 507 acres |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Round Lake
Water Quality Trend: ↓ Declining
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.376 m/yr | 4 |
| Phosphorus | ↓ Declining | +0.4 µg/L/yr | 7 |
| Chlorophyll-a | ↓ Declining | +0.11 µg/L/yr | 7 |
EPA Impairment Status
Round Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MI041000060101-02 · Official waterbody report · Matched by proximity (2.97 km)
County Ranking
Ranked #2 of 5 lakes in Lenawee County
Nearby Lakes in Lenawee County
Frequently asked questions about Round Lake
Where is Round Lake?
- Round Lake is a lake in Lenawee County, Michigan. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Round Lake?
- Round Lake in Lenawee County, Michigan has a water quality grade of A (Excellent). Water clarity: 12.3 ft visibility. Phosphorus: 8 µg/L. Chlorophyll-a (algae): 2 µg/L. Maximum depth: 67 ft. Surface area: 507.3 acres.
Is Round Lake safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Round Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
What is the water temperature of Round Lake?
- Round Lake typically sits around 60°F at the surface in September, from 1,397 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
How deep is Round Lake?
- Round Lake has a maximum depth of 67 feet. The lake covers 507.3 acres.
What fish are in Round Lake?
- Fish species found in Round Lake include Blackchin shiner, Blacknose shiner, Bluegill, Bluntnose minnow, Brook silverside, Brook stickleback, Creek chub, Golden shiner, Grass pickerel, Iowa darter, Johnny darter, Lake chubsucker, Largemouth bass, Longnose gar, Northern longear sunfish, Pumpkinseed, Rock bass, Smallmouth bass, Spotfin shiner, Spottail shiner, Tadpole madtom, Western banded killifish, White bass, Yellow bullhead, Yellow perch. Round Lake is located in Lenawee County, Michigan.
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Low nutrients, clear water. The letter is not a swimming clearance.
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Where this data comes from
69 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_MICORPS69 samples · 2016–2023
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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