Johnson Lake
Clearwater County, Minnesota63 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Johnson Lake. Here is what has been measured.
- Mesotrophic
- 70 ft max depth
- Public access
Johnson Lake in Clearwater County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 7.7 ft visibility. Phosphorus: 26 µg/L. Chlorophyll-a (algae): 7.6 µg/L. Maximum depth: 70 ft. Surface area: 63.04 acres.
Minnesota DNR's Standard Survey on June 12, 2023 caught 2.33 walleye per gill net at Johnson Lake. DNR survey details →
Johnson Lake is a 63-acre mesotrophic lake in Clearwater County, Minnesota with a maximum depth of 70 feet. Overall water quality is improving over recent sampling years. The lake supports 9 documented fish species including black bullhead, bluegill, and brown bullhead. Public access is available with 1 public boat landing. Compared to the 36 other monitored lakes in Clearwater County, Johnson Lake ranks #29 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-10. Methodology: how these readings are compared.
What Johnson Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing9 species recorded
- Deep water70 ft surveyed max depth
Swimming conditions
Readings onlyModerate algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
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 Minnesota Pollution Control Agency and the Minnesota DNR 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 Minnesota PCA 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.
Moderate clarity, visible to about 7.7 ft. Phosphorus 26 µg/L. Chlorophyll-a 7.6 µg/L. TSI 50.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7.7ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 26µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 7.6µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 50 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Johnson Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Johnson Lake typically sits around 51°F at the surface in September. Summer average is about 51°F. Usually warmest in Jul (about 52°F) and coldest in May (about 48°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (48°F) to its warmest (52°F).
Typical surface water temperature by month, from 561 field readings (2011–2025) via the EPA Water Quality Portal. See the full Johnson Lake water temperature breakdown →
Minnesota DNR's Standard Survey on June 12, 2023 caught 2.33 walleye per gill net at Johnson Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Johnson Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2023-06-12 (Standard Survey).
8 surveys on file · most recent 2023-06-12 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 40.94 | 5–8 in 2023-06-12 | 0.12 lb |
| Yellow Perch | 39.11 | 5–9 in 2023-06-12 | 0.18 lb |
| Pumpkinseed | 6.48 | 3–5 in 2023-06-12 | 0.07 lb |
| Northern Pike | 3.85 | 15–26 in 2023-06-12 | 1.66 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Black Bullhead
Yellow Perch
Pumpkinseed
Northern Pike
From the 2023-06-12 survey
Johnson Lake (also known as Grant Lake) is a 63-acre, undeveloped natural lake located 8 miles northeast of Clearbrook in northern Clearwater County. Johnson has an average water clarity of 7 feet and a maximum depth of 70 feet. Johnson Lake has multiple small inlets and one outlet connecting to the Clearwater River.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Johnson Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — JohnsonFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Johnson (1704)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — JohnsonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — JohnsonPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
70 ft
Surface area
63 acres
Shoreline
2.1 mi
Littoral zone
25%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,266 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Johnson LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Johnson Lake
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Top-rated places to stay near Johnson Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Johnson Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Improving-1.11 µg/L/yr6 years
Chlorophyll-a
Worsening+0.42 µg/L/yr6 years
Nearby Lakes in Clearwater County
Frequently asked questions about Johnson Lake
Where is Johnson Lake?
- Johnson Lake is a lake in Clearwater County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Johnson Lake?
- Johnson Lake in Clearwater County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 7.7 ft visibility. Phosphorus: 26 µg/L. Chlorophyll-a (algae): 7.6 µg/L. Maximum depth: 70 ft. Surface area: 63.04 acres.
Is Johnson Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Johnson Lake?
- Johnson Lake typically sits around 51°F at the surface in September, from 561 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Johnson Lake?
- Johnson Lake has a maximum depth of 70 feet. The lake covers 63.04 acres.
What fish are in Johnson Lake?
- Fish species found in Johnson Lake include black bullhead, bluegill, brown bullhead, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow perch. Johnson Lake is located in Clearwater County, Minnesota.
What did the DNR fisheries survey find at Johnson Lake?
- Minnesota DNR's Standard Survey on June 12, 2023 caught 2.33 walleye per gill net at Johnson Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Johnson Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Johnson Lake?
- Johnson Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Johnson Lake. Public access is listed as yes.
Can I fish at Johnson Lake?
- Johnson Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
90 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA90 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory