O'Rourke Lake is a cold, clear oligotrophic lake in Otsego County, Michigan. Water quality is graded A based on 1 sampling years through 2022. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 12 other monitored lakes in Otsego County, O'Rourke Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2022-09-17. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 15.5 ft down. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15.5 ft | A |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near O'Rourke Lake
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Top-rated places to stay near O'Rourke Lake
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Fishing O'Rourke Lake
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +9.78 m/yr | 2 |
Recreation & Access
Location
County Ranking
Ranked #6 of 13 lakes in Otsego County
Nearby Lakes in Otsego County
Explore O'Rourke Lake across LakeGrade
Fish species and top-graded lakes across Michigan
Fish species and best lakes in Otsego County
Species activity outlook by water temperature and season
Where to stay at Michigan's top lakes, each with its grade
Low nutrients, clear water, excellent for swimming
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More Michigan Lake Rankings
Other Grade A Lakes in Michigan
Charlevoix County · Clarity: 17 ft
Cheboygan County · Clarity: 32 ft
Montmorency County · Clarity: 13 ft
Kalkaska County · Clarity: 13.5 ft
Kalkaska County · Clarity: 18.5 ft
Kalkaska County · Excellent
Oligotrophic Lakes in Michigan
More records, surveys & data sources
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Data Sources
Water quality data from the EPA Water Quality Portal
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2022-09-17
Monitoring stations: 1