Johnson Lake
Roosevelt County, Montana144 acresView mapDirections
No nutrient or algae sampling on record from Montana DEQ for this lake.
Johnson Lake in Roosevelt County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Surface area: 144 acres.
Johnson Lake is a 144-acre lake in Roosevelt County, Montana.
Source: EPA Water Quality Portal sampling records, Montana DEQ. Methodology: how these readings are compared.
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Johnson Lake is safe to swim in today is a call for the Montana Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Johnson Lake
These are the measurements Montana DEQ publishes for Johnson Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. TSI undefined.
Ask about Johnson Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
144 acres
Shoreline
2.8 mi
No bathymetric survey has been published for Johnson Lake, so its depth is not documented here.
Stays via Stay22
Stays near Johnson Lake
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Frequently asked questions about Johnson Lake
Where is Johnson Lake?
- Johnson Lake is a lake in Roosevelt County, Montana. Its water-quality measurements are published by Montana DEQ and shown on this page as reported.
What is the water quality of Johnson Lake?
- Johnson Lake in Roosevelt County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Surface area: 144 acres.
Is Johnson Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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Where this data comes from
Measurements for Johnson Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.