Lake Ottawa
Iron County, Michigan531 acresView mapDirections
EGLE publishes the water-quality measurements for Lake Ottawa. Here is what has been measured.
- Limited data
Lake Ottawa in Iron County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 19.5 ft visibility. Surface area: 531.4 acres.
Lake Ottawa is a 531-acre lake in Iron County, Michigan. Water clarity is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2022-08-28. Methodology: how these readings are compared.
What Lake Ottawa is good for
From access and monitoring records, not editorial picks.
- Clear water19.5 ft of visibility
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Lake Ottawa 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 Lake Ottawa
These are the measurements EGLE publishes for Lake Ottawa, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 19.5 ft down. TSI 34.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 19.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| 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. | 34 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Lake Ottawa
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
531 acres
No bathymetric survey has been published for Lake Ottawa, so its depth is not documented here.
Stays via Stay22
Stays near Lake Ottawa
Compare lakeside cabins, hotels, and vacation rentals near Lake Ottawa in Iron County, Michigan — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Lake Ottawa
Prices for Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Michigan’s top lakes →
Follow Lake Ottawa’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Lake Ottawa
Water Quality Trend: Stable
Based on 6 years of monitoring (2017–2023).
Water clarity
Improving6 years
Phosphorus
Worsening+0.57 µg/L/yr6 years
Nearby Lakes in Iron County
Frequently asked questions about Lake Ottawa
Where is Lake Ottawa?
- Lake Ottawa 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 Lake Ottawa?
- Lake Ottawa in Iron County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 19.5 ft visibility. Surface area: 531.4 acres.
Is Lake Ottawa safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Lake Ottawa across LakeQuality
Fish species and the cleanest lakes across Michigan
Fish species and best lakes in Iron County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Upper Peninsula area
Where to stay at Michigan's top lakes, each with its readings
Michigan's cleanest lakes, ranked on agency measurements
More lakes in Michigan
Other Lakes in Michigan
Oligotrophic Lakes in Michigan
Where this data comes from
29 measurements from 1 monitoring station, 2017–2022. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- North American Lake Management Society
NALMS29 samples · 2017–2022
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.