
Lake County Lake Quality
Montana, 38 lakes, measured by Montana DEQ
There are 38 monitored lakes in Lake County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. 7 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. For Lake County the spread behind the average matters more than the average itself: a few nutrient-rich lakes among many clear ones produce the same figure as the inverse.
Most of the county's monitored lakes are shallow, under 50 feet, which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Swan Lake North End has the lowest nutrient and algae readings in the county.
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Quick Answers for Lake County
Planning a trip? Check special fishing regulations for Swan Lake North End — or check the official Montana fishing regulations.
All Lakes in Lake County
38 lakes · 7 ranked on readings, 31 without enough sampling7 lakes ranked on readings · 31 without enough sampling, hidden
| # | Lake | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|
| 1 | Swan Lake North EndLake | No recent samples | 3.1 µg/L | 1.1 µg/L | No recent samples | Not recorded |
| 2 | East Bay LakeLake | No recent samples | 3 µg/L | No recent samples | No recent samples | Not recorded |
| 3 | Big Arm Bay LakeLake | No recent samples | 1.5 µg/L | No recent samples | No recent samples | ✓ Public |
| 4 | Loon LakeLake | No recent samples | 6.7 µg/L | 2.2 µg/L | No recent samples | ✓ Public |
| 5 | Mary Ronan Lake WestLake | No recent samples | 33.6 µg/L | 4.7 µg/L | No recent samples | Not recorded |
| 6 | Jette LakeLake | No recent samples | 16.6 µg/L | 4.7 µg/L | No recent samples | Not recorded |
| 7 | Mary Ronan Lake EastLake | No recent samples | 15.8 µg/L | 3.5 µg/L | No recent samples | Not recorded |
| Flathead LakeLake | 11.8 ft | No recent samples | No recent samples | No recent samples | ✓ Public | |
| Lake Mary RonanLake | 16.8 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| Jette LakeLake | 15.8 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| Mission ReservoirLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Saint Marys LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Lucifer LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Lake of the CloudsLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Cliff LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| First LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| McDonald LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Ashley LakesLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Ninepipe ReservoirLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Kicking Horse ReservoirLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Summit LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Long LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Crow Creek LakesLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Crow Creek LakesLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Terrace LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Piper LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Pablo ReservoirLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Horte ReservoirLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Lower Crow ReservoirLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Loon LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Turtle LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Cedar LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Van LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Wymore LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Horseshoe LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Row LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Black LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| Skags LakeLake | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded |
NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.
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Source: the Montana Department of Environmental Quality. See data sources.