Ottawa Lake
Iron County, Michigan531 acresView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
↓ down from A at the last regrade
- Oligotrophic
- #14 of 21 in the county
- Public access
- Limited data
Ottawa Lake in Iron County, Michigan has a water quality grade of B (Good). Water clarity: 19.3 ft visibility. Phosphorus: 10 µg/L. Surface area: 531.4 acres.
- Clarity
- 19.3 ft
- Area
- 531 acres
- Type
- Oligotrophic
- Phosphorus
- 10 µg/L
- Trend
- → Stable
- Public access
- Yes
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Ottawa Lake is a 531-acre cold, clear oligotrophic lake in Iron County, Michigan. Water quality is graded B based on 1 sampling years through 2023. Water clarity is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 20 other monitored lakes in Iron County, Ottawa Lake ranks #14 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2023-08-27. Grade methodology: LakeQuality methodology.
What Ottawa Lake is good for
From access and monitoring records, not editorial picks.
- Clear water19.3 ft of visibility
- Boat launch1 documented ramp
- Camping1 public campground nearby
Swimming Safety
Grade onlyLimited data
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 B is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: B (Good)
Crystal clear, you can see 19.3 ft down. Phosphorus 10 µg/L. TSI 36. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 19.3 ft | Not graded |
| Phosphorus | 10 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 36 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 531 acres |
| Public Access | Yes |
No bathymetric survey has been published for Ottawa Lake, so its depth is not documented here.
Recreation & Access
- Lake OttawaPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Ottawa Lake
- Lake Ottawa Camp0.4 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Fishing Ottawa Lake
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.03 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.57 µg/L/yr | 6 |
County Ranking
Ranked #14 of 21 lakes in Iron County
Nearby Lakes in Iron County
Frequently asked questions about Ottawa Lake
Where is Ottawa Lake?
- Ottawa Lake is a lake in Iron County, Michigan. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Ottawa Lake?
- Ottawa Lake in Iron County, Michigan has a water quality grade of B (Good). Water clarity: 19.3 ft visibility. Phosphorus: 10 µg/L. Surface area: 531.4 acres.
Is Ottawa Lake safe to swim in?
- The B is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Are there boat ramps on Ottawa Lake?
- Ottawa Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lake Ottawa. Public access is listed as yes.
Are there campgrounds on Ottawa Lake?
- Ottawa Lake has 1 public campground from USGS The National Map within 5 km, including Lake Ottawa Camp. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Ottawa Lake across LakeQuality
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Fish species and best lakes in Iron County
Species activity outlook by water temperature and season
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Where to stay at Michigan's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
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Where this data comes from
45 measurements from 1 monitoring station, 2017–2023. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- Michigan EGLE - MiCorps
21MICH_MICORPS45 samples · 2017–2023
Analytical methods
- Phosphorus by Colorimetry
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
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles